Boosting High-Rate Zinc-Storage Performance by the Rational Design of Mn2O3 Nanoporous Architecture Cathode

"Anchoring Capture" Effect Mimicking Proline in Hardy Deep-Sea Fish to Stabilize the Zinc Anode with Lower Operating Temperature

The low plating/stripping efficiency of zinc anodes, dendrite growth, and high freezing points of aqueous solutions hinder the practical application of aqueous zinc-ion batteries. This paper proposes a zwitterionic permeable network solid-state electrolyte based on the "anchor-capture" effect to address these problems by incorporating proline (Pro, a biological antifreeze agent) into the electrolyte. Extensive validation tests, Quantum Chemistry (QC) calculations, Molecular Dynamics (MD) Simulations, and ab initio molecular dynamics simulations consistently indicate that the amino groups in proline adsorb onto the Zn metal surface, stabilizing the zinc anode-electrolyte interface, suppressing side reactions from water decomposition, and homogenizing zinc-ion flux. This electrolyte demonstrates excellent reversibility in Zn-Mn2O3 cells and Zn-Zn half-cells, achieving a high coulombic efficiency of over 99.4% across 2000 cycles in Zn-Mn2O3 full cells, and delivering a discharge-specific capacity of 175.2 mAh g-1 at -35 °C and 1 A g-1. Additionally, an appropriate concentration of proline lowers the electrolyte's freezing point to -45 °C through the network's solid-state effect, ensuring the stable operation of the solid-state battery at -35 °C. This innovative concept of network solid-state electrolytes injects new vitality into the development of multifunctional solid-state electrolytes.

An interactive dual energy storage mechanism boosts high-performance aqueous zinc-ion batteries

Organic materials are promising cathodes for aqueous zinc-ion batteries (AZIBs) due to their cost-effectiveness, environmental friendliness, and tunable structures. However, the energy density of AZIBs remains limited by the inherently low capacity and output voltage of organic cathode materials. To address this challenge, we develop a Mn ion-doped polyaniline (PAM) by harnessing the joint merits of the highly reversible doping process of the conjugated backbone and the unique dissolution-deposition behavior of Mn2+ in ZnSO4 electrolyte. The incorporation of Mn2+ into the PANI backbone facilitates the stabilization of PAM at high potentials by lowering the lowest unoccupied molecular orbital (LUMO) energy level, resulting in enhanced output voltage and cycling stability. This new interactive dual energy storage mechanism, illustrated by density functional theory calculations and ex situ characterization, contributes to the improved capacity by employing a dissolution-deposition storage mechanism. The battery showcases a maximum specific capacity of 496.7 mA h g-1 at an ultra-high working voltage of 2.4 V. And the capacity is 213.2 mA h g-1 when the current density reaches 20 A g-1. This molecular design of the pre-doped PANI cathode and the insight into the groundbreaking dual energy storage mechanism offer a new alternative host for high-performance Zn-organic batteries.

N, S-Codoped 3D Carbon Protected Nanoporous MnS With Record High Sodium Ion Storage Performance for Potential Industry Applications

With a high theoretical capacity, the MnS anode, however, exhibits a rather complex sodium diffusion kinetics and poor mechanical stability that hinder its application in sodium-ion batteries (SIBs). In this work, a simple, economical, and scalable strategy is developed to inherently coat nanoporous MnS with a 3D N, S co-doped thin carbon layer by using commercially available MnCO3 as precursors. Specifically, the strategy involves a two-step annealing process, which converts the MnCO3 microparticles into nanoporous Mn2O3 and MnS step by step. The 3D N, S codoped carbon layer is in situ formed during the second annealing process by first coating the nanoporous Mn2O3 with a polyaniline layer. Due to the inherent 3D carbon protection and the strong electronic interaction between N, S dopants and MnS, the N, S codoped carbon protected MnS obtained at 900 °C (NS-C@MnS-900) anode displays a high specific capacity of 845 mAh g-1 at 0.1 A g-1, which is higher than all reported MnS-based SIB anodes. It also shows an outstanding cyclability and rate performance, maintaining a stable capacity of ≈493 mAh g-1 after 1300 cycles at 10 A g-1, which is also the best according to knowledge. These exceptional electrochemical performances and the scalable/simple/low-cost synthesis make the NS-C@MnS-900 attractive for industry application.

Realizing the Electrode Engineering Significance Through Porous Organic Framework Materials for High-Capacity Aqueous Zn-Alkaline Battery

Energy storage technologies are eminently developed to address renewable energy utilization efficiently. Porous framework materials possess high surface area and pore volume, allowing for efficient ion transportation and storage. Their unique structure facilitates fast electron transfer, leading to improved battery kinetics. Porous organic framework materials like metal-organic (MOF) and covalent organic (COF) frameworks have immense potential in enhancing the charge/discharge performances of aqueous Zn-alkaline batteries. Organic frameworks and their derivatives can be modified feasibly to exhibit significant chemical stability, enabling them to tolerate the harsh battery environment. Zn-alkaline batteries can achieve enhanced energy density, longer lifespan, and improved rechargeability by incorporating MOFs and COFs, such as electrodes, separators, or electrolyte additives, into the battery architecture. The present review highlights the significant electrode design strategies based on porous framework materials for aqueous Zn-alkaline batteries, such as Zn-Ni, Zn-Mn, Zn-air, and Zn-N2/NO3 batteries. Besides, the discussion on the issues faced by the Zn anode and the essential anode design strategies to solve the issues are also included.

Insights into the cycling stability of manganese-based zinc-ion batteries: from energy storage mechanisms to capacity fluctuation and optimization strategies

Manganese-based materials are considered as one of the most promising cathodes in zinc-ion batteries (ZIBs) for large-scale energy storage applications owing to their cost-effectiveness, natural availability, low toxicity, multivalent states, high operation voltage, and satisfactory capacity. However, their intricate energy storage mechanisms coupled with unsatisfactory cycling stability hinder their commercial applications. Previous reviews have primarily focused on optimization strategies for achieving high capacity and fast reaction kinetics, while overlooking capacity fluctuation and lacking a systematic discussion on strategies to enhance the cycling stability of these materials. Thus, in this review, the energy storage mechanisms of manganese-based ZIBs with different structures are systematically elucidated and summarized. Next, the capacity fluctuation in manganese-based ZIBs, including capacity activation, degradation, and dynamic evolution in the whole cycle calendar are comprehensively analyzed. Finally, the constructive optimization strategies based on the reaction chemistry of one-electron and two-electron transfers for achieving durable cycling performance in manganese-based ZIBs are proposed.

Manganese-Based Oxide Cathode Materials for Aqueous Zinc-Ion Batteries: Materials, Mechanism, Challenges, and Strategies

Aqueous zinc-ion batteries (AZIBs) have recently attracted worldwide attention due to the natural abundance of Zn, low cost, high safety, and environmental benignity. Up to the present, several kinds of cathode materials have been employed for aqueous zinc-ion batteries, including manganese-based, vanadium-based, organic electrode materials, Prussian Blues, and their analogues, etc. Among all the cathode materials, manganese (Mn)-based oxide cathode materials possess the advantages of low cost, high theoretical specific capacity, and abundance of reserves, making them the most promising cathode materials for commercialization. However, several critical issues, including intrinsically poor conductivity, sluggish diffusion kinetics of Zn2+, Jahn-Teller effect, and Mn dissolution, hinder their practical applications. This Review provides an overview of the development history, research status, and scientific challenges of manganese-based oxide cathode materials for aqueous zinc-ion batteries. In addition, the failure mechanisms of manganese-based oxide materials are also discussed. To address the issues facing manganese-based oxide cathode materials, various strategies, including pre-intercalation, defect engineering, interface modification, morphology regulation, electrolyte optimization, composite construction, and activation of dissolution/deposition mechanism, are summarized. Finally, based on the analysis above, we provide future guidelines for designing Mn-based oxide cathode materials for aqueous zinc-ion batteries.

Recent Advances on Stretchable Aqueous Zinc-Ion Batteries for Wearable Electronics

The rapid development of wearable electronics has stimulated the pursuit of advanced stretchable power sources. As a promising candidate, stretchable aqueous zinc-ion batteries (AZIBs), have attracted unprecedented attention owing to their intrinsic safety, low cost, environmental benignity, and high performance, and can be endowed with additional functionalities to broaden the applications of wearable electronics. Here, a comprehensive review on the latest advances of stretchable AZIBs is presented. The materials and methods for stretchable components in AZIBs are first summarized, covering current collectors, electrodes, electrolytes/separators, and encapsulating layers. Subsequently, the benefits of the coplanar, fiber-shaped, and sandwiched configurations for stretchable AZIBs are analyzed. Moreover, the additional features integrated into stretchable AZIBs are highlighted. Finally, the challenges and prospects of stretchable AZIBs for wearable applications in the future are proposed.

Layered Topological Insulator MnBi2Te4 as a Cathode for a High Rate Performance Aqueous Zinc-Ion Battery

Recently, the topological insulator MnBi2Te4 has aroused great attention owing to its exotic quantum phenomena and intriguing device applications, but the superior performances of MnBi2Te4 have not been researched in the field of electrochemistry. By theoretical calculations, it is found that MnBi2Te4 exhibits excellent Zn2+ storage and transport properties. Therefore, it is speculated that MnBi2Te4 has excellent electrochemical performance in zinc-ion batteries (ZIBs). In this research, MnBi2Te4 as a pioneer has been explored in ZIBs, showing surprising electrochemical properties. The MnBi2Te4 electrode displays a high average discharge specific capacity (264.8 mA h g-1 at 0.40 A g-1), a competitive cycle life (88.6% of initial capacity after 400 cycles at 4.00 A g-1), and an excellent rate performance (average capacity retention rate of 95.1% from 0.40 to 8.00 A g-1) owing to the fast ion transport of the conductive topological surface state and dissipationless channel of the edge state. Surprisingly, the quasi-solid-state (QSS) MnBi2Te4/Zn battery delivers excellent Zn2+ storage capability and possesses a capacity retention of 79.9% after 1000 cycles at 4.00 A g-1. In addition, the QSS MnBi2Te4/Zn battery can exhibit excellent performance and the GCD curves maintain stability without distortion deformation even at temperatures of 0 and 75 °C.

A Static Tin-Manganese Battery with 30000-Cycle Lifespan Based on Stabilized Mn3+/Mn2+ Redox Chemistry

High-potential Mn³⁺/Mn²⁺ redox couple (>1.3 V vs SHE) in a static battery system is rarely reported due to the shuttle and disproportionation of Mn³⁺ in aqueous solutions. Herein, based on reversible stripping/plating of the Sn anode and stabilized Mn²⁺/Mn³⁺ redox couple in the cathode, an aqueous Sn-Mn full battery is established in acidic electrolytes. Sn anode exhibits high deposition efficiency, low polarization, and excellent stability in acidic electrolytes. With the help of H⁺ and a complexing agent, a reversible conversion between Mn²⁺ and Mn³⁺ ions takes place on the graphite surface. Pyrophosphate ligand is initially employed to form a protective layer through a complexation process with Sn⁴⁺ on the electrode surface, effectively preventing Mn³⁺ from disproportionation and hindering the uncontrollable diffusion of Mn³⁺ to electrolytes. Benefiting from the rational design, the full battery delivers satisfied electrochemical performance including a large capacity (0.45 mAh cm^-2 at 5 mA cm^-2), high discharge plateau voltage (>1.6 V), excellent rate capability (58% retention from 5 to 30 mA cm^-2), and superior cycling stability (no decay after 30 000 cycles). The battery design strategy realizes a robustly stable Mn³⁺/Mn²⁺ redox reaction, which broadens research into ultrafast acidic battery systems.

Material Design and Energy Storage Mechanism of Mn-Based Cathodes for Aqueous Zinc-Ion Batteries

Mn-based cathodes have been widely explored for aqueous zinc-ion batteries (ZIBs), by virtue of their high theoretical capacity and low cost. However, Mn-based cathodes suffer from poor rate capability and cycling performance. Researchers have presented various approaches to address these issues. Therefore, these endeavors scattered in various directions (e. g., designing electrode structures, defect engineering and optimizing electrolytes) are necessary to be connected through a systematic review. Hence, we comprehensively overview Mn-based cathode materials for ZIBs from the aspects of phase compositions, electrochemical behaviors and energy storage mechanisms, and try to build internal relations between these factors. Modification strategies of Mn-based cathodes are then introduced. Furthermore, this review also provides some new perspectives on future efforts toward high-energy and long-life Mn-based cathodes for ZIBs.

Insight on Cathodes Chemistry for Aqueous Zinc-Ion Batteries: From Reaction Mechanisms, Structural Engineering, and Modification Strategies

By virtue of low cost, eco-friendliness, competitive gravimetric energy density, and intrinsic safety, more and more attention has increasingly focused on aqueous zinc ion batteries (AZIBs) as a promising alternative for scalable energy storage. However, plagued by a complex interfacial process, sluggish dynamics, lability of electrodes and electrolytes, insufficient energy density, and poor cycle life heavily restrict practical applications of AZIBs, indicating that profound understandings on cathode storage chemistry are necessarily needed. Hence, this paper comprehensively summarizes recent advance in cathodes with critical insight on the energy storage mechanism. Furthermore, the issues and challenges for high-performance cathodes are meticulously explored, presenting inspiring structural engineering and modification strategies. Finally, rational evaluations on representative cathodes are rendered, suggesting the potential development direction of AZIBs.

Surface-Alloyed Nanoporous Zinc as Reversible and Stable Anodes for High-Performance Aqueous Zinc-Ion Battery

Metallic zinc (Zn) is one of the most attractive multivalent-metal anode materials in post-lithium batteries because of its high abundance, low cost and high theoretical capacity. However, it usually suffers from large voltage polarization, low Coulombic efficiency and high propensity for dendritic failure during Zn stripping/plating, hindering the practical application in aqueous rechargeable zinc-metal batteries (AR-ZMBs). Here we demonstrate that anionic surfactant-assisted in situ surface alloying of Cu and Zn remarkably improves Zn reversibility of 3D nanoporous Zn electrodes for potential use as high-performance AR-ZMB anode materials. As a result of the zincophilic Zn_xCu_y alloy shell guiding uniform Zn deposition with a zero nucleation overpotential and facilitating Zn stripping via the Zn_xCu_y/Zn galvanic couples, the self-supported nanoporous Zn_xCu_y/Zn electrodes exhibit superior dendrite-free Zn stripping/plating behaviors in ambient aqueous electrolyte, with ultralow polarizations under current densities up to 50 mA cm^‒2, exceptional stability for 1900 h and high Zn utilization. This enables AR-ZMB full cells constructed with nanoporous Zn_xCu_y/Zn anode and K_zMnO₂ cathode to achieve specific energy of as high as ~ 430 Wh kg^‒1 with ~ 99.8% Coulombic efficiency, and retain ~ 86% after long-term cycles for > 700 h.

New Insight on K2 Zn2 V10 O28 as an Advanced Cathode for Rechargeable Aqueous Zinc-Ion Batteries

Aqueous zinc-ion batteries (ZIBs) have recently attracted people's extensive attention in their application in energy storage systems resulting from their exclusive characteristics of low cost and environmental compatibility. However, finding suitable cathode materials continues to be the major challenge. Polyoxovanadates (POVs), as an important branch of polyoxometalates (POMs), are considered as a promising electrode material for reversible aqueous ZIBs relying on the flexible valence state of V. Herein, POVs (K₂ Zn₂ V₁₀ O₂₈ : KZVO) are reported as an advanced cathode for storing Zn²⁺ , which delivers a high discharge capacity of 223.4 mAh g^-1 at 0.1 A g^-1 , considerable energy density (182.9 Wh kg^-1 ) and power density (40.38 W kg^-1 ), and robust cyclic performance. In addition, the dynamic properties of the KZVO/Zn battery are revealed by pseudocapacitance analysis and GITT tests. Meanwhile, the storage mechanism of Zn²⁺ is further analyzed by ex situ XRD, XPS, TEM, and HRTEM. Overall, this work not only draws up a cathode material for the POMs system in aqueous ZIBs, but also demonstrates that POMs are the rising star in energy storage and electric energy applications.

Entropy-Assisted High-Entropy Oxide with a Spinel Structure toward High-Temperature Infrared Radiation Materials

Developing advanced materials with a high-entropy concept is one of the hot trends in materials science. The configurational entropy of high-entropy materials can be tuned by introducing different atomic species, which can also impart a result in excellent physical and chemical properties. In this work, we synthesized a solid-solution oxide (Cu, Mn, Fe, Cr)₃O₄ by a simple and scalable solid-phase synthesis method. We extensively investigated the microstructure and chemical composition, indicating that (Cu, Mn, Fe, Cr)₃O₄ has a single-phase spinel structure. Simultaneously, we reasonably evaluated the position occupied by the elements of (Cu, Mn, Fe, Cr)₃O₄ in a spinel structure as (Cu_0.75Fe_0.25)(Fe_0.25Cr_0.375Mn_0.375)₂O₄. Here, we first evaluated the infrared radiation performance of (Cu, Mn, Fe, Cr)₃O₄. The new, high-entropy oxide (HEO) (Cu, Mn, Fe, Cr)₃O₄ powder exhibits high infrared emissivity values of 0.879 and 0.848 in the wavelengths of 0.78-2.5 and 2.5-16 μm, respectively, and has excellent thermal stability. More importantly, the infrared emissivity values of as-prepared HEO coating reach 0.955 (0.78-2.5 μm) at room temperature and 0.936 (3-16 μm) at 800 °C. This work provides a viable strategy toward the laboratory mass production of this HEO for infrared radiation materials, which shows great potential in the energy-related applications.

Hierarchical MXene/transition metal chalcogenide heterostructures for electrochemical energy storage and conversion

MXenes have gained rapidly increasing attention owing to their two-dimensional (2D) layered structures and unique mechanical and physicochemical properties. However, MXenes have some intrinsic limitations (e.g., the restacking tendency of the 2D structure) that hinder their practical applications. Transition metal chalcogenide (TMC) materials such as SnS, NiS, MoS₂, FeS₂, and NiSe₂ have attracted much interest for energy storage and conversion by virture of their earth-abundance, low costs, moderate overpotentials, and unique layered structures. Nonetheless, the intrinsic poor electronic conductivity and huge volume change of TMC materials during the alkali metal-ion intercalation/deintercalation process cause fast capacity fading and poor-rate and poor-cycling performances. Constructing heterostructures based on metallic conductive MXenes and highly electrochemically active TMCs is a promising and effective strategy to solve these problems and enhance the electrochemical performances. This review highlights and discusses the recent research development of MXenes and hierarchical MXene/TMC heterostructures, with a focus on the synthesis strategies, surface/heterointerface engineering, and potential applications for lithium-ion batteries, sodium-ion batteries, lithium-sulfur batteries, supercapacitors, electrocatalysis, and photocatalysis. The critical challenges and perspectives of the future development of MXenes and hierarchical MXene/TMC heterostructures for electrochemical energy storage and conversion are forecasted.

In Situ Defect Induction in Close-Packed Lattice Plane for the Efficient Zinc Ion Storage

In situ electrochemical activation brings unexpected electrochemical performance improvements to electrode materials, but the mechanism behind it still needs further study. Herein, an electrochemically in situ defect induction in close-packed lattice plane of vanadium nitride oxide (VN_x O_y ) in aqueous zinc-ion battery is reported. It is verified by theoretical calculation and experiment that the original compact structure is not suitable for the insert of Zn²⁺ ion, while a highly active one after the initial electrochemical activization accompanied by the in situ defect induction in close-packed lattice plane of VN_x O_y exhibits efficient zinc ion storage. As expected, activated VN_x O_y can achieve very high reversible capacity of 231.4 mA h g^-1 at 1 A g^-1 and cycle stability upto 6000 cycles at 10 A g^-1 with a capacity retention of 94.3%. This work proposes a new insight for understanding the electrochemically in situ transformation to obtain highly active cathode materials for the aqueous zinc-ion batteries.

Recent Advances on Spinel Zinc Manganate Cathode Materials for Zinc-Ion Batteries

Zinc metal is abundant in nature, non-toxic, harmless, and cheap. Zinc-ion batteries (ZIBs) have also emerged as the times require, which has attracted scholars' research interest. In the zinc-ion batteries, the cathode material is indispensable. Manganese oxides are widely used in electrode materials because of their various valence states (+2, +3, +4, +7). ZnMn₂ O₄ (ZMO) is a mixed metal oxide with a spinel structure similar to LiMn₂ O₄ . Due to the synergistic effect of Zn and Mn, it has the advantages of high theoretical capacity. In recent years, researchers have gradually applied ZnMn₂ O₄ to zinc ion batteries. In order to obtain high-energy-density zinc ion batteries, it is also very important to match electrolytes with a wide operating voltage window and develop a highly reversible anode. In the first instance, we investigate the research progress of spinel ZnMn₂ O₄ as a reliable candidate material for zinc ion batteries. Later on, we review the optimization and modification measures of anode and electrolyte to improve the electrochemical properties of spinel ZnMn₂ O₄ . On this basis, we propose the reasonable research direction and development prospects for this material. It is hoped that there will be a help to researchers in this field.

Constructing metal-organic framework-derived Mn2O3multishelled hollow nanospheres for high-performance cathode of aqueous zinc-ion batteries

Herein, we successfully synthesize Mn₂O₃multishelled hollow nanospheres through simply oxidizing Mn-based metal-organic framework microspheres. The number of the shells reaches 4. Many cavities and nanograins are hidden underneath the shell. The multishelled hollow structure brings about a wide hierarchical mesopore size range, large pore volume (0.26 cm³g^-1) and high specific surface area (117.6 m²g^-1). The superior zinc-ion storage performance may be achieved. The reversible capacity reaches 453 mAh g^-1at current density of 0.1 A g^-1. After 500 cycles at 1 A g^-1, the discharge capacity of 152.8 mAh g^-1is still delivered. The discharge capacity at 1.5 A g^-1stabilizes at 107 mAh g^-1. The zinc storage process is further studied through kinetics analyses. It is found that in the zinc storage process, ion diffusion process and capacitive process occur simultaneously, and the capacitive process is dominant. The excellent electrochemical performance is mainly attributed to the multishelled hollow nanosphere structure of Mn₂O₃. This structure promotes contact of electrode materials/electrolyte, offers more active sites, facilitates infiltration of electrolyte, buffer volume change of Mn₂O₃, improving electrochemical activity, reaction kinetics and cycling performance of Mn₂O₃. Overall, Mn₂O₃multishelled hollow nanosphere is an excellent cathode material for aqueous zinc-ion batteries.

Cathode materials for aqueous zinc-ion batteries: A mini review

Although lithium-ion batteries (LIBs) have many advantages, they cannot satisfy the demands of numerous large energy storage industries owing to their high cost, low security, and low resource richness. Aqueous zinc-ion batteries (ZIBs) with low cost, high safety, and high synergistic efficiency have attracted an increasing amount of attention and are considered a promising choice to replace LIBs. However, the existing cathode materials for ZIBs have many shortcomings, such as poor electron and zinc ion conductivity and complex energy storage mechanisms. Thus, it is crucial to identify a cathode material with a stable structure, substantial limit, and suitability for ZIBs. In this review, several typical cathode materials for ZIBs employed in recent years and their detailed energy storage mechanisms are summarized, and various methods to enhance the electrochemical properties of ZIBs are briefly introduced. Finally, the existing problems and expected development directions of ZIBs are discussed.

Constructing the Efficient Ion Diffusion Pathway by Introducing Oxygen Defects in Mn2O3 for High-Performance Aqueous Zinc-Ion Batteries

Mn-based cathodes are admittedly the most promising candidate to achieve the practical applications of aqueous zinc-ion batteries because of the high operating voltage and economic benefit. However, the design of Mn-based cathodes still remains challenging because of the vulnerable chemical architecture and strong electrostatic interaction that lead to the inferior reaction kinetics and rapid capacity decay. These intrinsic drawbacks need to be fundamentally addressed by rationally decorating the crystal structure. Herein, an oxygen-defective Mn-based cathode (Oc_u-Mn₂O₃) is designed via a doping low-valence Cu-ion strategy. The oxygen defect can modify the internal electric field of the material and enhance the substantial electrostatic stability by compensating for the nonzero dipole moment. With the merits of oxygen deficiency, the Oc_u-Mn₂O₃ electrode exhibits the significant diffusion coefficient in the range from 1 × 10^-6 to 1 × 10^-8, and good rate performance. In addition, the Oc_u-Mn₂O₃ maintains the highly reversible cyclic stability with the capacity retention of 88% over 600 cycles. The charge storage mechanism is explored as well, illustrating that the oxygen defects can improve the electrochemical active sites of H⁺ insertion, achieving a better charge-storage capacity than Mn₂O₃.