A Better Zn-Ion Storage Device: Recent Progress for Zn-Ion Hybrid Supercapacitors

A high-voltage Zn-ion hybrid supercapacitor based on a conjugated polyphthalocyanine framework cathode and a Zn@Zn phthalocyanine anode through the pH-decoupling strategy

Aqueous Zn-ion hybrid supercapacitors have shown extraordinary promise for electrochemical energy storage, due to low cost, high security, large power density and acceptable energy density. Rational optimization of electrodes and electrolytes has always been the key for boosting the electrochemical energy storage performances of aqueous Zn-ion hybrid supercapacitors. We propose a pH-decoupling Zn-ion hybrid supercapacitor based on a conjugated polyphthalocyanine (PPc) framework cathode and a Zn@Zn phthalocyanine (Pc) anode. Many structural characterizations indicate that the porous PPc framework possesses the different chemical structure from the symmetrical intermediate. The PPc electrode provides higher gravimetric specific capacitances in the ZnSO4/H2SO4 electrolyte than those in the ZnSO4 electrolyte and the H2SO4 electrolyte. Compered to the Zn anode, the Zn@ZnPc anode exhibits the longer cycle life of Zn-ion hybrid supercapacitors, more obvious suppression on hydrogen evolution reaction, better infiltration property of the electrolyte and the larger adsorption energy for the chemisorption of a bare Zn2+ ion. Electrochemical kinetics analysis of the pH-decoupling PPc//Zn@ZnPc supercapacitor confirms the predominant capacitive-controlled capacity for energy storage, due to physical adsorption and chemical adsorption of electrolyte ions for producing electric double layer capacitance and pseudocapacitance respectively. Additionally, theoretical calculation confirms the appropriate adsorption energy of the bridging N atoms for the highly reversible adsorption/desorption of Zn(H2O)62+. This assembly strategy of the pH-decoupling PPc//Zn@ZnPc supercapacitor opens up a new avenue for exploiting high-performance aqueous Zn-ion hybrid supercapacitors.

Facile preparation of carbon and nitrogen co-doped NiMoO4·MoO2 heterostructures derived from polyoxometalates with ultrahigh energy density for zinc-ion capacitors

Aqueous zinc ion hybrid supercapacitors (ZHSCs) have attracted great attention in recent years. However, their electrochemical performance is impeded by their low energy density and poor cycling stability, mainly due to the difficulty in effectively activating the ionic and electronic conductivity of the cathode material. In this work, we innovatively propose a low-cost, precisely customized strategy for doping trace amounts of carbon and nitrogen elements into metal oxides to improve electrochemical performance. The carbon- and nitrogen-doped NiMoO4·MoO2/NC heterostructures derived from polyoxometalates maintain high electrochemical activity while achieving high ionic conductivity. Trace amounts of carbon and nitrogen elements can significantly improve electronic conductivity and charge storage capacity. Due to the synergistic contribution, the composite structure with multi-redox sites exhibits a high specific capacity value of 364.96 F g-1 at 1 A g-1 in 1 M ZnSO4. A ZHSC was assembled with NiMoO4·MoO2/NC as the cathode and a zinc sheet as the anode. After 10 000 cycles, the capacitance retention rate still reached over 80%. In addition, its energy density and power density can also reach 102 W h kg-1@4140 W kg-1, which is higher than those of MoO2-based traditional supercapacitors. This strategy fully demonstrates the great practicality and development prospects of polyoxometalate derivatives for ZHSCs.

A Ce3+/4+ Redox Couple-Promoted Aqueous Zinc-Ion Hybrid Capacitor: Design Strategies and Mechanistic Insights

Aqueous zinc-ion hybrid capacitors (ZIHCs) are emerging as promising energy storage devices owing to several desirable attributes including good safety, high power density, and good stability. However, the limited energy density mainly caused by the low specific capacity of porous carbon cathodes hinders the practical application of ZIHCs. A Ce3+/4+ redox couple-promoted aqueous ZIHC (Ce-ZIHC) is designed with the addition of Ce3+/4+ electrolyte additives. The Ce3+/4+ redox couple is shown to markedly increase the specific capacity of the porous carbon cathode energy and enhance the stability of Zn2+ stripping/plating at the Zn metal anode. Notably, the as-constructed Ce-ZIHC performs more than twice the energy density of the ZIHC with the commercial activated carbon cathode. Furthermore, the Ce-ZIHC shows a low self-discharge rate and can work stably for more than 60 000 cycles at 5.0 A g-1. This work highlights the great potential of Ce3+/4+ redox couple in improving the overall performance of ZIHCs toward practical application.

Top-Down Strategy Enabling Elastic Wood Nanocarbon Sponges with Wrinkled Multilayer Structure and High Compressive Strength for High-Performance Compressible Supercapacitors

3D porous carbon electrodes have attracted significant attention for advancing compressible supercapacitors (SCs) in flexible electronics. The micro- and nanoscale architecture critically influences the mechanical and electrochemical performance of these electrodes. However, achieving a balance between high compressive strength, electrochemical stability, and cost-effective sustainable production remains challenging. Here, a superelastic wood nanocarbon sponge (WNCS) with a wrinkled multilayer structure is developed via a facile "top-down" design on natural wood. These unique wrinkled nanolayers effectively alleviate stress concentration through elastic deformation, resulting in a high compressive strength of 580.6 kPa at 70% reversible strain. The significantly increased specific surface area, coupled with abundant micro-mesopores and highly graphitized nanocarbon, promotes rapid ion/electron transport, enabling the WNCS to achieve an ultrahigh capacitance of 4.21 F cm-2 at 1 mA cm-2, along with excellent cyclic stability and rate capability. Furthermore, an asymmetric supercapacitor (ASC) using a WNCS anode and a NiCo-layered double hydroxide cathode retains 71.8% of its initial capacitance after 1000 compression cycles and withstands stress up to 1.03 MPa without capacitance degradation. This sustainable, cost-effective WNCS shows great promise for flexible, compressible, and wearable electrochemical energy systems.

MOF-Derived Transition Metal Phosphides for Supercapacitors

Transition metal phosphides (TMPs) in supercapacitors (SCs) applications are increasingly attracting attention because of their exceptional electrochemical performance. MOF-derived TMPs, possess high specific surface areas, rich pore structure, and controllable chemical compositions, offering promising opportunities for supercapacitor applications. There is a wide variety of MOF-derived TMPs, and they exhibit different properties in SCs. This work mainly categorizes MOF-derived TMPs (FexP, CoxP, NixP, NixCoyP, CuxP), and then outlines the latest research advancements regarding their use as electrode materials in SCs, including the latest results of synthesis methods and structural modulation. Subsequently, the applications of MOF-derived TMPs as electrode materials in SCs are discussed. At the end, perspectives of future developments and key challenges in the applications of MOF-derived TMPs in SCs are highlighted, with the aim of providing guidance for future research.

Simulation of Interface Characteristics and Charge Transfer Dynamics for Layered Electrodes Using Cascade Capacitance in Supercapacitors by COMSOL Software

In this investigation, the performance disparity between layer-by-layer (LbL) electrodes and uniformly mixed (UM) electrodes in supercapacitors is evaluated using COMSOL Multiphysics software by utilizing a two-dimensional asymmetric structure simulation model where the LbL electrodes consist of ZnMn2O4 and graphene oxide (GO) with varying layering sequences and scales ranging from millimeters to microns. The results revealed that the LbL electrodes significantly augmented the supercapacitor's performance by enhancing charge and mass transport mechanisms. Across both millimeter and micrometer scales, the LbL electrodes surpassed the uniformly mixed electrodes due to their larger surface area and greater ionic accessibility, resulting in more effective charge storage and faster electron transfer. Cyclic voltammetry (CV) illustrated that the peak current density of the LbL electrodes increased with an increase in layers with four-layer micrometer-scale electrodes displaying characteristics closest to those of an ideal supercapacitor, showcasing more consistent and efficient energy storage and release capabilities. The analysis using electrochemical impedance spectroscopy (EIS) revealed that the LbL electrodes exhibited reduced resistance and significant capacitive characteristics about 109 F/m2. The stacked structure not only improved the surface area and conductivity of the electrodes but also accelerated the charge transfer process, minimized interfacial reaction resistance, and facilitated ion diffusion within the electrodes. Through a combination of simulation techniques and theoretical analysis, this study proposed a stacked capacitance (Cs) theory and developed a cross-scale electrochemical interface model by integrating first-principles calculations with multiscale simulations. These findings provide valuable insights for designing and optimizing high-performance materials and devices, offering a new perspective on enhancing the supercapacitor performance through electrode design.

Insights of Zinc Ion Storage in Chilli-Stem Derived Porous Carbon Enabling Ultrastability and High Energy Density of Zinc-Ion Hybrid Supercapacitors

Aqueous zinc ion hybrid supercapacitors (ZIHSCs) are promising as low-cost and safe energy storage devices for next-generation applications. Still, their energy-power performance and durability are far from satisfactory. Here, we present an energy-dense, and ultrastable ZIHSC realized using activated porous carbons derived from chilli-stems. KOH activation resulted in a high specific surface area of 1710 m2/g, abundant mesoporous structure, and oxygen functionalities, which helped the KOH-activated carbon (CSK) to yield an impressive specific capacity and energy density of 192 mA h/g and 172 W h/kg, respectively, and makes it the top-performing ZIHSC in recent times. ZIHSC's cycling performance is exceptional, retaining over 90% capacity even after 50,000 charge-discharge cycles. Molecular dynamics simulations reveal easy Zn ion diffusion through interconnected channels and subsequent pore fillings within the carbon electrodes, rendering impressive performance. Simulations further reveal important atomic interactions, demonstrating that higher currents drawn from the device cause partial filling of pores and blockages in the channels and result in a decrease in the device's specific capacity. Benefitted by CSK's impressive performance, the aqueous Zn@pCu//CSK full-cell device has demonstrated good energy-power densities (57.7 W h/kg and 4.5 k W/kg) and durability over tens of thousands of cycles, further substantiating ZIHSCs' application prospects in real life.

Multiple Heteroatom Doped Nanoporous Biocarbon for Supercapacitor and Zinc-ion Capacitor

The use of nanoporous carbon for energy storage has seen a significant rise due to its exciting properties such as high surface area, hierarchical porosity and exceptional electrochemical properties. These unique advantages of exceptional surface and electrochemical properties of these porous carbon nanostructures can be coupled with the individual doping of heteroatoms such as S, N, O, and B for achieving high energy storage capacity and stability. Herein, we integrated the synthesis of carbon nitride (CN) and borocarbonitride (BCN) with solid state activation for introducing multiple heteroatoms (B, N, O, and S) onto the nanoporous carbon frameworks. The produced materials exhibit abundance of micro and mesoporosity, a high surface area of 2909 m2 g-1, and a pore volume of 0.87 cm3 g-1. Also, it offers an exceptional capacitance of 233.5 F g-1 at 0.5 A g-1 with 3 M KOH as electrolyte. Further, the optimised material was explored as cathode in zinc ion capacitor which delivers an energy and power density of 50.4 Wh kg-1 and 400 W kg-1 respectively in addition to high cyclability. Studies on the formation of the intermediate phases during charging/discharging of the cell through ex situ characterization result in some useful insights into the stability of ZIC.

Controllable construction of a 3D-honeycomb-like porous carbon network as a high-performance cathode for promoting Zn-ion storage capability

Inheriting the energy storage mechanism of supercapacitors and rechargeable ion batteries, zinc ion capacitors (ZICs) greatly increase their energy density at high power without sacrificing their life span. However, sluggish kinetics and insufficient active sites for Zn2+ storage induced by the significant mismatch of charge carriers with limited pore size hinder the efficient Zn2+ storage and smooth application of carbonaceous cathode materials. Herein, a three-dimensional honeycomb-like porous carbon network (HPCN) was fabricated, which can reduce the diffusion barrier for fast kinetics, produce a high-density defect area, effectively increase active sites for charge storage, and generate a high nitrogen-doping content. Benefiting from these advantages, the optimized ZICs bring out a marvelous energy/power density (130 W h kg-1/11.7 kW kg-1) with an ultrahigh reliable cyclability of 97.8% after 50 000 cycles at a high current density of 5 A g-1. Importantly, systematic ex situ characterizations combined with theoretical calculations demonstrate that the outstanding Zn2+ storage capacity is attributed to the synergistic effect of physical co-adsorption of cations and reversible chemisorption. This work presents an attractive strategy for developing advanced carbon cathodes with suitable pores and accelerates the exploration of charge storage mechanisms, which may open a new avenue for practical supercapacitors.

Customizable Metal Micromesh Electrode Enabling Flexible Transparent Zn-Ion Hybrid Supercapacitors with High Energy Density

Emerging flexible and wearable electronic products are placing a compelling demand on lightweight transparent energy storage devices. Owing to their distinguishing features of safety, high specific energy, cycling stability, and rapid charge/discharge advantages, Zn-ion hybrid supercapacitors are a current topic of discussion. However, the trade-off for optical transmittance and energy density remains a great challenge. Here, a high-performance Zn-ion hybrid supercapacitor based on the customizable ultrathin (5 µm), ultralight (0.45 mg cm-2), and ultra-transparent (87.6%) Ni micromesh based cathode and Zn micromesh anode with the highest figure of merit (84 843) is proposed. The developed flexible transparent Zn-ion hybrid supercapacitors reveal excellent cycle stability (no decline after 20 000 cycles), high areal energy density (31.69 µWh cm-2), and high power density (512 µW cm-2). In addition, the assembled solid flexible and transparent Zn-ion hybrid supercapacitor with polyacrylamide gel electrolyte shows extraordinary mechanical properties even under extreme bending and twisting operation. Furthermore, the full device displays a high optical transmittance over 55.04% and can be conformally integrated with diverse devices as a flexible transparent power supply. The fabrication technology offers seamless compatibility with industrial manufacturing, making it an ideal model for the advancement of portable and wearable devices.

Multifunctional Zincophilic Hydrogel Electrolyte with Abundant Hydrogen Bonds for Zinc-Ion Capacitors and Supercapacitors

The new-generation flexible Zn-ion capacitors (ZICs) require multifunctionality and environmental adaptability for practical applications. This essentially means that hydrogel electrolytes are expected to possess superior mechanical properties, temperature resistance, and tunable interface properties to resist flexibility loss and performance degradation over a wide operating temperatures range. Herein, a multifunctional polyzwitterionic hydrogel electrolyte (PAM/LA/PSBMA) with wide operating temperatures, excellent tensile ability, high water retention, and self-adhesion is designed. Molecular dynamics simulations and experimental results show that polar functional groups (-COO-, -SO3-, -C═O, and -NHCO-) in the hydrogel can form abundant hydrogen bonds with water molecules, which can destroy the original hydrogen bonds (HBs) network between the water molecules and have a low freezing point. It can also form coordination with Zn2+, so that the deposition of Zn2+ electric field homogenization effectively alleviates the growth of Zn dendrites. On this basis, the constructed Zn//Zn cell can be stably cycled 290 h at 10 mA cm-2 (1 mA h cm-2). The constructed ZICs and supercapacitor have a high specific capacitance, excellent energy density, good ionic conductivity, and long cycling stability. This study provides guidance on molecular design for the development of integrated multifunctional smart electronic devices that are environmentally adaptable, resistant to drying, and highly flexible.

Cobalt Ion-Stabilized VO2 for Aqueous Ammonium Ion Hybrid Supercapacitors

Aqueous ammonium ion hybrid supercapacitor (A-HSC) is an efficient energy storage device based on nonmetallic ion carriers (NH4+), which combines advantages such as low cost, safety, and sustainability. However, unstable electrode structures are prone to structural collapse in aqueous electrolytes, leading to fast capacitance decay, especially in host materials represented by vanadium-based oxidation. Here, the Co2+ preintercalation strategy is used to stabilize the VO2 tunnel structure and improve the electrochemical stability of the fast NH4+ storage process. In addition, the understanding of the NH4+ storage mechanism has been deepened through ex situ structural characterization and electrochemical analysis. The results indicate that Co2+ preintercalation effectively enhances the conductivity and structural stability of VO2, and inhibits the dissolution of V in aqueous electrolytes. In addition, the charge storage mechanisms of NH4+ intercalation/deintercalation and the reversible formation/fracture of hydrogen bonds were revealed.

Intercalation chemistry engineering strategy enabled high mass loading and ultrastable electrodes for High-Performance aqueous electrochemical energy storage devices

Aqueous electrochemical energy storage devices (AEESDs) are considered one of the most promising candidates for large-scale energy storage infrastructure due to their high affordability and safety. Developing electrodes with the merits of high energy density and long lifespan remains a challenging issue toward the practical application of AEESDs. Research attempts at electrode materials, nanostructure configuration, and electronic engineering show the limitations due to the inherent contradictions associated with thicker electrodes and ion-accessible kinetics. Herein, we propose an intercalation chemistry engineering strategy to enhance the electrolyte ion (de)intercalation behaviors during the electrochemical charge-discharge. To validate this strategy, the prototypical model of a high-mass-loading MnO2-based electrode is used with controlled intercalation of Na+ and H2O. Theoretical and experimental results reveal that an optimal content of Na+ and H2O on the MnO2-based electrode exhibits superior electrochemical performance. Typically, the resultant electrode exhibits an impressive areal capacitance of 1551 mF/cm2 with a mass loading of 9.7 mg/cm2 (at 1 mA/cm2). Furthermore, the assembled full-cell with obtained MnO2-based electrode delivers a high energy density of 0.12 mWh/cm2 (at 20.02 mW/cm2) and ultra-high cycling stability with a capacitance retention percentage of 89.63 % (345 mF/cm2) even after 100,000 cycles (tested over 72 days).

π-Conjugated molecule mediated self-doped hierarchical porous carbons via self-stacking interaction for high-energy and ultra-stable zinc-ion hybrid capacitors

Understanding the self-stacking interactions in precursors can facilitate the preparation of high-performance carbon materials and promote the commercial application of zinc ion hybrid capacitors (ZIHCs). Here, a π-conjugated molecule mediated pyrolysis strategy is presented to prepare carbon materials. Taking intermolecular force simulation (reduced density gradient plots) as a guide, the relationship between the self-stacking interactions in π-conjugated molecules and the structural parameters of carbon materials can be extrapolated. The resultant self-doped hierarchical porous carbons (NHPCs) derived from 1, 8, 4, 5-naphthalenetetracarboxdiimide with suitable self-stacking interactions empower the highest specific surface areas (2038 m2/g) and surface opening macropores. The NHPCs-based ZIHCs deliver a high capacity of 220 mAh/g, a high energy density of 149.5 Wh kg-1 and a super-stable cycle lifespan with 93.2 % capacity retention after 200, 000 cycles. The excellent electrochemical performance roots in the superior hierarchical porous structure with surface opening macropores, which guarantees the structural stability of carbon cathodes upon repeated rounds. Meanwhile, the heteroatom doping further relieves the kinetics concern of Zn2+ uptake/removal to enhance O-Zn-N binding particularly at high discharge currents. Besides, the proton-assisted Zn2+ dual-ion storage mechanism plays an essential role in the energy storage process. This work demonstrates a facile synthesis method and advances the fundamental understanding of its dual-ion storage mechanism.

Oxygen-enriched pitch-derived hierarchically porous carbon toward boosted zinc-ion storage performance

The lack of cathode materials with satisfactory Zn2+ storage capability substantially hinders the realization of high-performance aqueous zinc-ion hybrid capacitors (ZHCs). Herein, we propose a facile KMnO4 template-assisted KOH activation strategy to prepare a novel oxygen-enriched hierarchically porous carbon (HPC-1-4). This strategy efficiently converts coal tar pitch (CTP) into a well-tuned carbon material with a large specific surface area of 3019 m2 g-1 and a high oxygen content of 9.20 at%, which is conducive to providing rich active sites, rapid charge transport, and appreciable pseudocapacitance for Zn-ion storage. Thus, the as-fabricated HPC-1-4-based aqueous ZHC exhibits prominent performance, including a high gravimetric capacity (206.7 mAh g-1 at 0.25 A g-1), a remarkable energy density (153.4 Wh kg-1 at 184.2 W kg-1), and an impressive power output (15240 W kg-1 at 63.5 Wh kg-1). In-depth ex-situ characterizations indicate that the excellent electrochemical properties of ZHCs are due to the synergistic effect of the Zn2+ adsorption mechanism and reversible chemisorption. In addition, the assembled quasi-solid-state device demonstrates excellent electrochemical stability of up to 100% capacity retention over 50000 cycles, accompanied with a desirable energy density of 115.6 Wh kg-1. The facile preparation method of converting CTP into carbonaceous functional materials has advanced the development of efficient and eco-friendly energy storage technologies.

Enabling Wasted A4 Papers as a Promising Carbon Source to Construct Partially Graphitic Hierarchical Porous Carbon for High-Performance Aqueous Zn-Ion Storage

Considering the superiorities of abundance, easy collection, low cost, and nearly constant composition, the wasted A4 papers are deemed as a recyclable and scalable carbon source to fabricate functional carbon materials for Zn-ion hybrid supercapacitors (ZIHSCs), which integrate the supercapacitors' high-power output and batteries' high energy density. Herein, the wasted A4 papers are efficiently converted into an advanced carbon material owning a hierarchical porous structure with a high surface area and interconnected multiscale channels, a graphitic structure, and a good level of N/O codoping. By taking advantage of these features, an express electron/ion transfer pathway, a large accessible surface interface, and a robust architecture are achieved for swift kinetics, numerous active sites, and excellent steadiness to afford a charming Zn2+ storage capability for the aqueous coin-type ZIHSC device (a high capacity of 244 mAh g-1 at 0.1 A g-1 with a capacity conservation of 116.4 mAh g-1 even amplifying the current density by 200 times, a supreme energy density of 190.4 Wh kg-1, a supreme power output of 18 kW kg-1, and an eminent durability of 93.8% over 10,000 cycles at 10 A g-1). Excitingly, the quasi-solid ZIHSC device also bespeaks an enjoyable capacity of 211.7 mAh g-1, a high energy density of 159.3 Wh kg-1, good mechanical flexibility, and a low self-discharge rate. This work puts forward a simple and scalable strategy to enable the wasted A4 paper as a competitive carbon source to construct advanced cathode material for Zn2+ storage.

Controllable synthesis of electric double-layer capacitance and pseudocapacitance coupled porous carbon cathode material for zinc-ion hybrid capacitors

The designability of the porous structure of carbon material makes it a popular material for zinc-ion hybrid capacitors (ZIHCs). However, the micropore confinement effect leads to sluggish kinetics and is not well resolved yet. In this work, a pore-size controllable carbon material was designed to enhance ion accessibility. The experimental and calculated results revealed that suitable pore sizes and defects were beneficial to ion transfer/adsorption. Meanwhile, oxygen-containing functional groups could introduce a pseudocapacitance reaction. Its large specific surface area and interconnecting network structure could shorten the ion/electron transfer length to reach high ion adsorption capacity and fast kinetic behavior. When used as a zinc-ion hybrid capacitor cathode material, it showed 9.9 kW kg-1 power density and 100 W h kg-1 energy density. Even at 5 A g-1, after 50 000 cycles, there was still 93% capacity retention. Systemic ex situ characterization and first-principles calculations indicated that the excellent electrochemical performance is attributed to the electric double layer capacitance (EDLC) - pseudocapacitance coupled mechanism via the introduction of an appropriate amount of oxygen-containing functional groups. This work provides a robust design for pore engineering and mechanistic insights into rapid zinc-ion storage in carbon materials.

MXene-Based Micro-Supercapacitors: Ink Rheology, Microelectrode Design and Integrated System

MXenes have shown great potential for micro-supercapacitors (MSCs) due to the high metallic conductivity, tunable interlayer spacing and intercalation pseudocapacitance. In particular, the negative surface charge and high hydrophilicity of MXenes make them suitable for various solution processing strategies. Nevertheless, a comprehensive review of solution processing of MXene MSCs has not been conducted. In this review, we present a comprehensive summary of the state-of-the-art of MXene MSCs in terms of ink rheology, microelectrode design and integrated system. The ink formulation and rheological behavior of MXenes for different solution processing strategies, which are essential for high quality printed/coated films, are presented. The effects of MXene and its compounds, 3D electrode structure, and asymmetric design on the electrochemical properties of MXene MSCs are discussed in detail. Equally important, we summarize the integrated system and intelligent applications of MXene MSCs and present the current challenges and prospects for the development of high-performance MXene MSCs.

Stretchable Zn‐Ion Hybrid Capacitor with Hydrogel Encapsulated 3D Interdigital Structure

To enhance the areal energy density of current flexible energy storage devices, hybrid capacitors combining the advantages of supercapacitors and batteries are proposed and further enhanced by incorporating the 3D interdigital structure design. However, uneven electric field distribution and hindered ion diffusion kinetics due to the non‐electroactive components in these devices limit the enhancement of areal electrochemical performances when expanding the electrodes longitudinally. Herein, hydrogels with high ionic conductivity and high mechanical stability are designed to accommodate Zn2+‐containing electrolytes and integrated with Ti3C2Tx‐MXene electrodes to assemble flexible Zn‐ion hybrid capacitors (ZIHCs). Fully encapsulated by ionic conductive hydrogels, 3D interdigital electrodes enable omnidirectional ion transport and unimpeded ionic accessibility, facilitating adequate electrode reactions, rapid energy storage, and uniform energy distribution. Hence, the all‐hydrogel‐encapsulated ZIHC achieved a 50‐fold increase in capacitance with a quadrupled electrode thickness, exhibiting a large areal capacitance of 1432 mF cm−2 and an energy density of 389.7 µWh cm−2 without sacrificing power density and rate performance. Finite element simulations further illustrate the uniform distribution of potential, electric field intensity, and energy density in this structure. In addition, the device shows great stability under deformation, excellent adhesion, and underwater workability, demonstrating great promise for next‐generation wearable energy storage devices.

High-energy-density zinc ion capacitors based on 3D porous free-standing defect-reduced graphene oxide hydrogel cathodes

Zinc ion capacitors (ZICs) have shown potential for breaking the energy density ceiling of traditional supercapacitors (SCs) via appropriate device design. Nevertheless, a significant challenge remains in advancing ZIC positive electrode materials with excellent conductivity, high specific capacitance, and reliable cycle stability. A highly attractive option for carbon-based electrode materials is reduced graphene oxide (RGO) due to its vast specific surface area, prominent porosity, and 3D cross-linked frame. However, the tight stacking of RGO sheets driven by van der Waals forces can restrict active sites, decrease specific capacitance, and elevate electrochemical impedance. To overcome these challenges, 3D defective RGO (DRGO) hydrogels were prepared by a metal Co cocatalytic gasification reaction. This method produced mesoporous defects on the surface of RGO hydrogels via a low-temperature hydrothermal self-assembly strategy. The surface of the layer has a wide and uniform distribution, which can offer abundant redox active sites, rich ion transfer channels, and fast reaction kinetics. In this work, 3D DRGO//Zn exhibited a wide operating window (0-1.8 V), high specific capacitance (189.39 F g-1 at 1 A g-1), outstanding energy density (85.23 W h kg-1 at 960.31 W kg-1; 52.36 W h kg-1 at 17454.87 W kg-1), and persistent cycling life (98.86% initial capacitance retention after 10 000 cycles at 10 A g-1). This study emphasizes the device design of ZIC and promising prospects of using 3D DRGO hydrogel as a feasible positive electrode for ZIC.

Ni3S2/Ni2O3 heterojunction anchored on N-doped carbon nanosheet aerogels for dual-ion hybrid supercapacitors

As a member of transition metal sulfides, Ni3S2 has been reported as one type of the effective pseudocapacitive electrode materials for supercapacitors, due to its good electrical conductivity and high electrochemical activity. To further improve the energy density of the Ni3S2-based supercapacitors, we propose a novel approach to the Ni3S2/Ni2O3 heterojunction anchored on N-doped carbon nanosheet aerogels (Ni3S2/Ni2O3@N-CNA), which is used as the cathode for Zn-ion hybrid supercapacitors with the dual-ion electrolytes. The Ni3S2/Ni2O3@N-CNA samples can be prepared through the bubble-templated polymerization of pyrrole and the carbonization of the polypyrrole nanosheet hydrogel/Ni2+. The Ni3S2/Ni2O3@N-CNA cathode is immersed into the Li-ion catholyte for Li+ storage, while the Zn foil anode is immersed into the Zn-ion anolyte for Zn2+ storage. Electrochemical kinetic analysis of the dual-ion hybrid supercapacitor indicates its evident capacitance characteristic. Additionally, theoretical calculations reveal that the Ni3S2/Ni2O3 heterojunction can facilitate the adsorption and dehydration of a hydrated Li+ ion to further play a great role in the enhancement of pseudocapacitance. Based on the novel strategy of the alkaline dual-ion electrolytes, this dual-ion hybrid supercapacitor with the high energy density (64.2 Wh kg-1) opens up a new avenue to develop high-performance Zn-ion hybrid supercapacitors.

Key to High Performance Ion Hybrid Capacitor: Weakly Solvated Zinc Cations

Zinc ion hybrid capacitors suffer from lack of reversibility and dendrite formation. An electrolyte, based on a solution of a zinc salt in acetonitrile and tetramethylene sulfone, allows smooth zinc deposition with high coulombic efficiency in a Zn||stainless steel cell (99.6% for 2880 cycles at 1.0 mA cm-2 , 1.0 mAh cm-2 ). A Zn||Zn cell operates stably for at least 7940 h at 1.0 mA cm-2 with an area capacity of 10 mAh cm-2 , or 648 h at 90% depth of discharge and 1 mA cm-2 , 9.0 mAh cm-2 . Molecular dynamics simulations reveal the reason for the excellent reversibility: The zinc cation is only weakly solvated than in pure tetramethylene sulfone with the closest atoms at 3.3 to 3.8 Å. With this electrolyte, a zinc||activated-carbon hybrid capacitor exhibits an operating voltage of 2.0 to 2.5 V, an energy-density of 135 Wh kg-1 and a power-density of 613 W kg-1 at 0.5 A g-1 . At the very high current-density of 15 A g-1 , 29.3 Wh kg-1 and 14 250 W kg-1 are achieved with 81.2% capacity retention over 9000 cycles.

Metal Negatrode Supercapatteries: Advancements, Challenges, and Future Perspectives for High-Performance Energy Storage

Metal negatrode supercapattery (MNSC) is an emerging technology that combines the high energy storage capabilities of batteries with the high-power delivery of supercapacitors, thereby offering promising solutions for various applications, such as energy storage systems, electric vehicles, and portable electronics. This review article presents a comprehensive analysis of the potential of MNSCs as a prospective energy storage technology. MNSCs utilize a specific configuration in which the negatrode consists of a metal or metal-rich electrode, such as sodium, aluminum, potassium, or zinc, whereas the positrode functions as a supercapacitor electrode. The utilization of negatrodes with low electrochemical potential and high electrical conductivity is crucial for achieving high specific energy in energy storage devices, despite facing numerous challenges. The present study discusses the design and fabrication aspects of MNSCs, including the selection of appropriate metal negatrodes, electrolytes, and positrodes, alongside the fundamental operational mechanisms. Additionally, this review explores the challenges encountered in MNSCs and proposes solutions to enhance their performance, such as addressing dendrite formation and instability of metal electrodes.

Sulfate template induced S/O doped carbon nanosheets enabling rich physi/chemi-sorption sites for high-performance zinc ion hybrid capacitors

Zinc ion hybrid capacitors (ZIHCs) are encouraging energy storage devices for large-scale applications. Nevertheless, the electrochemical performance of ZIHCs is often limited by the cathode materials which show low energy density and rate capability practically. One of the efficient strategies to overcome these challenges is the development of advanced carbon cathode materials with abundant physi/chemisorption sites. Herein, we develop a sulfate template strategy to prepare sulfur and oxygen doped carbon nanosheets (SOCNs) as a potential cathode active material for ZIHCs. The as-prepared SOCNs exhibit porous architectures with a large surface area of 1877 m2 g-1, substantial structural defects, and high heteroatom-doped contents (O: 7.9 at%, S: 0.7 at%). These exceptional features are vital to enhancing Zn ion storage. Consequently, the SOCN cathode shows a high capacity of 151 mAh g-1 at 0.1 A g-1, high cycle stability with 83% capacity retention at 5 A g-1 after 4000 cycles, and a superior energy density of 103.1 Wh kg-1. We also investigate the dynamic adsorption/desorption behaviors of Zn ions and anions of the ZIHCs carbon electrodes during the process of charge and discharge by ex-situ experiments. This work highlights the significance of the integration with a large specific surface area and bountiful heteroatoms in carbon electrodes for achieving high-performance ZIHCs.

Hydrogel Electrolyte Enabled High-Performance Flexible Aqueous Zinc Ion Energy Storage Systems toward Wearable Electronics

To cater to the swift advance of flexible wearable electronics, there is growing demand for flexible energy storage system (ESS). Aqueous zinc ion energy storage systems (AZIESSs), characterizing safety and low cost, are competitive candidates for flexible energy storage. Hydrogels, as quasi-solid substances, are the appropriate and burgeoning electrolytes that enable high-performance flexible AZIESSs. However, challenges still remain in designing suitable and comprehensive hydrogel electrolyte, which provides flexible AZIESSs with high reversibility and versatility. Hence, the application of hydrogel electrolyte-based AZIESSs in wearable electronics is restricted. A thorough review is required for hydrogel electrolyte design to pave the way for high-performance flexible AZIESSs. This review delves into the engineering of desirable hydrogel electrolytes for flexible AZIESSs from the perspective of electrolyte designers. Detailed descriptions of hydrogel electrolytes in basic characteristics, Zn anode, and cathode stabilization effects as well as their functional properties are provided. Moreover, the application of hydrogel electrolyte-based flexible AZIESSs in wearable electronics is discussed, expecting to accelerate their strides toward lives. Finally, the corresponding challenges and future development trends are also presented, with the hope of inspiring readers.

3D Hierarchical Ti3C2TX@PANI-Reduced Graphene Oxide Heterostructure Hydrogel Anode and Defective Reduced Graphene Oxide Hydrogel Cathode for High-Performance Zinc Ion Capacitors

The practical application of supercapacitors (SCs) has been known to be restricted by low energy density, and zinc ion capacitors (ZICs) with a capacitive cathode and a battery-type anode have emerged as a unique technology that can effectively mitigate the issue. To this end, the design of electrodes with low electrochemical impedance, high specific capacitance, and outstanding reaction stability represents a critical first step. Herein, we report the synthesis of hierarchical Ti3C2TX@PANI heterostructures by uniform deposition of conductive polyaniline (PANI) polymer nanofibers on the exposed surface of the Ti3C2TX nanosheets, which are then assembled into a three-dimensional (3D) cross-linking framework by a graphene oxide (GO)-assisted self-convergence hydrothermal strategy. This resulting 3D Ti3C2TX@PANI-reduced graphene oxide (Ti3C2TX@PANI-RGO) heterostructure hydrogel shows a large surface area (488.75 F g-1 at 0.5 A g-1), outstanding electrical conductivity, and fast reaction kinetics, making it a promising electrode material. Separately, defective RGO (DRGO) hydrogels are prepared by a patterning process, and they exhibit a broad and uniform distribution of mesopores, which is conducive to ion transport with an excellent specific capacitance (223.52 F g-1 at 0.5 A g-1). A ZIC is subsequently constructed by utilizing Ti3C2TX@PANI-RGO as the anode and DRGO as the cathode, which displays an extensive operating voltage (0-3.0 V), prominent energy density (1060.96 Wh kg-1 at 761.32 W kg-1, 439.87 Wh kg-1 at 9786.86 W kg-1), and durable cycle stability (retaining 67.9% of the original capacitance after 4000 cycles at 6 A g-1). This study underscores the immense prospect of the Ti3C2TX-based heterostructure hydrogel and DRGO as a feasible anode and cathode for ZICs, respectively.

Fabrication of N-Doped Porous Carbon with Micro/Mesoporous Structure from Furfural Residue for Supercapacitors

N-doping is a very useful method to improve the electrochemical performance of porous carbon (PC) materials. In this study, the potential of furfural residue (FR), a solid waste in furfural production, as a precursor to producing PC materials for supercapacitors was highlighted. To obtain an N-doped PC with a high specific surface area (SSA) and hierarchical porous structure, the urea-KOH synergistic activation method was proposed. The obtained FRPCK-Urea showed a high SSA of 1850 m2 g-1, large pore volume of 0.9973 cm3 g-1, and interconnected micro/mesoporous structure. Besides, urea can also serve as a nitrogen source, resulting in a high N content of 5.31% in FRPCK-Urea. These properties endow FRPCK-Urea with an excellent capacitance of 222.7 F g-1 at 0.5 A g-1 in 6 mol L-1 KOH aqueous electrolyte in a three-electrode system. The prepared FRPCK-Urea possessed a well capacitance retention at current densities from 0.5 to 20 A g-1 (81.90%) and cycle durability (96.43% after 5000 cycles), leading to FRPCK-Urea to be a potential electrode material for supercapacitors. Therefore, this work develops an effective way for the high-valued utilization of FR.

Redox Electrolytes-Assisting Aqueous Zn-Based Batteries by Pseudocapacitive Multiple Perovskite Fluorides Cathode and Charge Storage Mechanisms

Aqueous Zn-based batteries (AZBs) have attracted intensive attention. However, to explore advanced cathode materials with in-depth elucidation of their charge storage mechanisms, improve energy storage capacity, and construct novel cell systems remain a great challenge. Herein, a new pseudocapacitive multiple perovskite fluorides (ABF3 ) cathode is designed, represented by KMF-(IV, V, and VI; M = NiCoMnZn/-Mg/-MgFe), and constructed Zn//KMF-(IV, V, and VI) AZBs and their flexible devices. Ex situ tests have revealed a typical bulk phase conversion mechanism of KMF-VI electrode for charge storage in alkaline media dominated by redox-active Ni/Co/Mn species, with transformation of ABF3 nanocrystals into amorphous metal oxide/(oxy)hydroxide nanosheets. By employing single or bipolar redox electrolyte strategies of 20 mm [Fe(CN)6 ]3- or/and 10 mm SO3 2- /Cu[(NH3 )4 ]2+ acting on KMF-(IV, V, and VI) cathode and Zn anode, the AZBs show an improved energy storage owing to additional capacity contribution of redox electrolytes. The as-designed Zn//polyvinyl alcohol (PVA)-KOH-K3 [Fe(CN)6 ]//KMF-(IV, V, and VI) redox gel electrolytes-assisting flexible AZBs (RGE-FAZBs) exhibit remarkable performance under different bending angles because of slight dissolution corrosion of zinc anode compared with liquid electrolytes. Overall, the work demonstrates the novel idea of conversion-type multiple ABF3 cathode for redox electrolytes-assisting AZBs (RE-AZBs) and their flexible systems, showing great significance on electrochemical energy storage.

Direct Synthesis of Mn3[Fe(CN)6]2·nH2O Nanosheets as Novel 2D Analog of Prussian Blue and Material for High-Performance Metal-Ion Batteries

Rechargeable metal-ion batteries (RMIBs) are prospective highly effective and low-cost devices for energy storage. Prussian blue analogues (PBAs) have become a subject of significant interest for commercial applications owing to their exceptional specific capacity and broad operational potential window as cathode materials for rechargeable metal-ion batteries. However, the limiting factors for its widespread use are its poor electrical conductivity and stability. The present study describes the direct and simple synthesis of 2D nanosheets of MnFCN (Mn₃[Fe(CN)₆]₂·nH₂O) on nickel foam (NF) via a successive ionic layer deposition (SILD) method, which provided more ion diffusion and electrochemical conductivity. MnFCN/NF exhibited exceptional cathode performance for RMIBs, delivering a high specific capacity of 1032 F/g at 1 A/g in an aqueous 1M NaOH electrolyte. Additionally, the specific capacitance reached the remarkable levels of 327.5 F/g at 1 A/g and 230 F/g at 0.1 A/g in 1M Na₂SO₄ and 1M ZnSO₄ aqueous solutions, respectively.

Bacterial Nanocellulose from Komagataeibacter Medellinensis in Fique Juice for Activated Carbons Production and Its Application for Supercapacitor Electrodes

This paper presents the results obtained from the chemical activation of bacterial nanocellulose (BCN) using fique juice as a culture medium. BNC activation (BNCA) was carried out with H3PO4 and KOH at activation temperatures between 500 °C to 800 °C. The materials obtained were characterized morphologically, physicochemically, superficially, and electrochemically, using scanning electron microscopy, X-ray photoelectron spectroscopy (XPS), the physisorption of gases N2 and CO2 at 77 K and 273 K, respectively, cyclic voltammetry, chronopotentiometry, and electrochemical impedance spectroscopy (EIS). The samples activated with H3PO4 presented specific surface areas (SBET) around 780 m2 g−1, while those activated with KOH values presented specific surface areas between 680 and 893 m2 g−1. The XPS analysis showed that the PXPS percentage on the surface after H3PO4 activation was 11 wt%. The energy storage capacitance values ranged between 97.5 F g−1 and 220 F g−1 by EIS in 1 M H2SO4. The samples with the best electrochemical performance were activated with KOH at 700 °C and 800 °C, mainly due to the high SBET available and the accessibility of the microporosity. The capacitance of BNCAs was mainly improved by electrostatic effects due to the SBET rather than that of pseudocapacitive ones due to the presence of phosphorus heteroatoms.

Synergistic effect of nitrogen and oxygen dopants in 3D hierarchical porous carbon cathodes for ultra-fast zinc ion hybrid supercapacitors

Zinc-ion hybrid supercapacitor is one of the most promising electrochemical energy storage devices for the applications needing both high energy densities and power densities. Nitrogen doping is an effective way to enhance the capacitive performance of porous carbon cathodes in zinc-ion hybrid supercapacitor. However, accurate evidence is yet needed to demonstrate how nitrogen dopants influence the charge storage of Zn²⁺ and H⁺ cations. Herein, we prepared 3D interconnected hierarchical porous carbon nanosheets by a one-step explosion method. The effect of nitrogen dopants on pseudocapacitance was analyzed by the electrochemical behaviors of as-prepared porous carbon samples with similar morphology and pore structure but different nitrogen and oxygen doping levels. Ex-situ XPS and DFT calculation demonstrate that nitrogen dopants promote the pseudocapacitive reactions by lowering the energy barrier for the change of oxidation states of carbonyl moieties. Owing to the improved pseudocapacitance by nitrogen/oxygen dopants and fast diffusion of Zn²⁺ ions in 3D interconnected hierarchical porous carbon matrix, the as-constructed ZIHCs show both high gravimetric capacitance (301 F g^-1 at 0.1 A g^-1) and excellent rate capability (a capacitance retention of 30% at 200 A g^-1).

Morphology engineering of biomass-derived porous carbon from 3D to 2D towards boosting capacitive charge storage capability

Carbon morphology significantly affects the capacitive performance of porous carbons. Biomass-derived porous carbons are usually restricted by inferior capacitive performance owing to their inherently three-dimensional (3D) blocked morphologies. Fabricating two-dimensional (2D) sheet-like morphology is expected to expose more inner space for better electrochemical performance, however, it needs to overcome the self-aggregation of biomass. The comprehensive understanding of how 2D morphology boosts capacitive performance remains challenging. Herein, we provide a morphology-regulating strategy to prepare 2D and 3D porous carbons and investigate the morphology effect on charge storage capability via both experimental data and theoretical simulations. 2D carbon exhibits better capacitance than 3D carbon in both electric double-layer capacitors (254 versus 211F g^-1) and zinc-ion hybrid supercapacitors (320 versus 232F g^-1), because the 2D carbon morphology not only improves the pore accessibility for higher double-layer capacitance, but also facilitates the exposure of active functional groups for more pseudocapacitance. Moreover, 2D morphology shortens pore length, leading to better anti-self-discharge capability. This study is beneficial to understanding the relationship between carbon morphology and capacitive performance and provides a facile strategy to upgrade biomass-derived porous carbons via morphology engineering.

Applications of Graphene in Five Senses, Nervous System, and Artificial Muscles

Graphene remains of great interest in biomedical applications because of biocompatibility. Diseases relating to human senses interfere with life satisfaction and happiness. Therefore, the restoration by artificial organs or sensory devices may bring a bright future by the recovery of senses in patients. In this review, we update the most recent progress in graphene based sensors for mimicking human senses such as artificial retina for image sensors, artificial eardrums, gas sensors, chemical sensors, and tactile sensors. The brain-like processors are discussed based on conventional transistors as well as memristor related neuromorphic computing. The brain-machine interface is introduced for providing a single pathway. Besides, the artificial muscles based on graphene are summarized in the means of actuators in order to react to the physical world. Future opportunities remain for elevating the performances of human-like sensors and their clinical applications.

Compacting Electric Double Layer Enables Carbon Electrode with Ultrahigh Zn Ion Storage Capability

Carbon-based cathodes for aqueous zinc ion hybrid supercapacitors (ZHSCs) typically undergo low Zn ion storage capability due to their electric double layer capacitance (EDLC) energy storage mechanism that is restricted by specific surface area and thickness of electric double layer (EDL). Here, we report a universal surface charge modulation strategy to effectively enhance the capacitance of carbon materials by decreasing the thickness of EDL. Amino groups with lone pair electrons were chosen to increase the surface charge density and enhanced the interaction between carbon electrode and Zn ions, thus effectively compacting the EDL. Consequently, amino functionalized porous carbon based ZHSCs can deliver an ultrahigh capacity of 255.2 mAh g^-1 along with excellent cycling stability (95.5 % capacity retention after 50 000 cycles) in 1 M ZnCl₂ electrolyte. This study demonstrates the feasibility of EDL modified carbon as Zn²⁺ storage cathode and great prospect for constructing high performance ZHSCs.

Investigation of High-Performance Electrode Materials: Processing and Storage Mechanism

The scope of the Special Issue entitled "Investigation of High-Performance Electrode Materials: Processing and Storage Mechanism" includes the research on electrodes of high-performance electrochemical energy storage and conversion devices (metal ion batteries, non-metallic ion batteries, metal-air batteries, supercapacitors, photocatalysis, electrocatalysis, etc [...].

Metal-organic frameworks and their derivatives for metal-ion (Li, Na, K and Zn) hybrid capacitors

Metal-ion hybrid capacitors (MIHCs) hold particular promise for next-generation energy storage technologies, which bridge the gap between the high energy density of conventional batteries and the high power density and long lifespan of supercapacitors (SCs). However, the achieved electrochemical performance of available MIHCs is still far from practical requirements. This is primarily attributed to the mismatch in capacity and reaction kinetics between the cathode and anode. In this regard, metal-organic frameworks (MOFs) and their derivatives offer great opportunities for high-performance MIHCs due to their high specific surface area, high porosity, topological diversity, and designable functional sites. In this review, instead of simply enumerating, we critically summarize the recent progress of MOFs and their derivatives in MIHCs (Li, Na, K, and Zn), while emphasizing the relationship between the structure/composition and electrochemical performance. In addition, existing issues and some representative design strategies are highlighted to inspire breaking through existing limitations. Finally, a brief conclusion and outlook are presented, along with current challenges and future opportunities for MOFs and their derivatives in MIHCs.

Efficient Recovery Annealing of the Pseudocapacitive Electrode with a High Loading of Cobalt Oxide Nanoparticles for Hybrid Supercapacitor Applications

Electrochemical pseudocapacitors, along with batteries, are the essential components of today's highly efficient energy storage systems. Cobalt oxide is widely developing for hybrid supercapacitor pseudocapacitance electrode applications due to its wide range of redox reactions, high theoretical capacitance, low cost, and presence of electrical conductivity. In this work, a recovery annealing approach is proposed to modify the electrochemical properties of Co₃O₄ pseudocapacitive electrodes. Cyclic voltammetry measurements indicate a predominance of surface-controlled redox reactions as a result of recovery annealing. X-ray diffraction, Raman spectra, and XPES results showed that due to the small size of cobalt oxide particles, low-temperature recovery causes the transformation of the Co₃O₄ nanocrystalline phase into the CoO phase. For the same reason, a rapid reverse transformation of CoO into Co₃O₄ occurs during in situ oxidation. This recrystallization enhances the electrochemical activity of the surface of nanoparticles, where a high concentration of oxygen vacancies is observed in the resulting Co₃O₄ phase. Thus, a simple method of modifying nanocrystalline Co₃O₄ electrodes provides much-improved pseudocapacitance characteristics.

Animal- and Human-Inspired Nanostructures as Supercapacitor Electrode Materials: A Review

Human civilization has been relentlessly inspired by the nurturing lessons; nature is teaching us. From birds to airplanes and bullet trains, nature gave us a lot of perspective in aiding the progress and development of countless industries, inventions, transportation, and many more. Not only that nature inspired us in such technological advances but also, nature stimulated the advancement of micro- and nanostructures. Nature-inspired nanoarchitectures have been considered a favorable structure in electrode materials for a wide range of applications. It offers various positive attributes, especially in energy storage applications, such as the formation of hierarchical two-dimensional and three-dimensional interconnected networked structures that benefit the electrodes in terms of high surface area, high porosity and rich surface textural features, and eventually, delivering high capacity and outstanding overall material stability. In this review, we comprehensively assessed and compiled the recent advances in various nature-inspired based on animal- and human-inspired nanostructures used for supercapacitors. This comprehensive review will help researchers to accommodate nature-inspired nanostructures in industrializing energy storage and many other applications.

Metal-Organic Framework Materials for Electrochemical Supercapacitors

Exploring new materials with high stability and capacity is full of challenges in sustainable energy conversion and storage systems. Metal-organic frameworks (MOFs), as a new type of porous material, show the advantages of large specific surface area, high porosity, low density, and adjustable pore size, exhibiting a broad application prospect in the field of electrocatalytic reactions, batteries, particularly in the field of supercapacitors. This comprehensive review outlines the recent progress in synthetic methods and electrochemical performances of MOF materials, as well as their applications in supercapacitors. Additionally, the superiorities of MOFs-related materials are highlighted, while major challenges or opportunities for future research on them for electrochemical supercapacitors have been discussed and displayed, along with extensive experimental experiences.