Controllable N-Doped CuCo2 O4 @C Film as a Self-Supported Anode for Ultrastable Sodium-Ion Batteries

Construction of N-doped carbon encapsulated Mn2O3/MnO heterojunction for enhanced lithium storage performance

Owing to high theoretical capacity, low cost and abundant availability, manganese oxides are widely viewed as promising anodes for lithium-ion batteries (LIBs). Nonetheless, their practical application is significantly hindered by poor electrical conductivity, sluggish reaction kinetics and substantial volume change. In this work, an ingenious polypyrrole encapsulation followed by pyrolysis strategy is proposed to produce N-doped carbon encapsulated Mn2O3/MnO heterojunction (Mn2O3/MnO@NC) by using mechanically ground Mn3O4/C3N4 mixture as the precursor. The results show that the selection of precursor plays a pivotal role in the successful preparation of Mn2O3/MnO@NC hybrid. It is revealed that the uniform encapsulation by N-doped carbon significantly enhances the conductivity and structural stability of the final product. Concurrently, the Mn2O3/MnO heterojunction within the resultant hybrid exhibits a unique quantum-dot size, which effectively shortens ion transport pathways and exposes the active sites for lithium storage. Additionally, experimental observations and theoretical calculations demonstrate that the built-in electric fields generated at the interfaces of Mn2O3/MnO heterojunction accelerate the charge transfer and ion diffusion, thereby enhancing the electrochemical reaction kinetics. As a result, the Mn2O3/MnO@NC hybrid displays much enhanced lithium storage performance. Evidently, our work offers a good guidance for the design and synthesis of advanced transition metal oxide/carbon anodes for LIBs.

Progress and Prospect of Bimetallic Oxides for Sodium-Ion Batteries: Synthesis, Mechanism, and Optimization Strategy

Sodium-ion batteries (SIBs) are considered as an alternative to and even replacement of lithium-ion batteries in the near future in order to address the energy crisis and scarcity of lithium resources due to the wide distribution and abundance of sodium resources on the earth. The exploration and development of high-performance anode materials are critical to the practical applications of advanced SIBs. Among various anode materials, bimetallic oxides (BMOs) have attracted special research attention because of their abundance, easy access, rich redox reactions, enhanced capacity and satisfactory cycling stability. Although many BMO anode materials have been reported as anode materials in SIBs, very limited studies summarized the progress and prospect of BMOs in practical applications of SIBs. In this review, recent progress and challenges of BMO anode materials for SIBs have been comprehensively summarized and discussed. First, the preparation methods and sodium storage mechanisms of BMOs are discussed. Then, the challenges, optimization strategies, and sodium storage performance of BMO anode materials have been reviewed and summarized. Finally, the prospects and future research directions of BMOs in SIBs have been proposed. This review aims to provide insight into the efficient design and optimization of BMO anode materials for high-performance SIBs.

Insights into performance and mechanism of ZnO/CuCo2O4 composite as heterogeneous photoactivator of peroxymonosulfate for enrofloxacin degradation

In this study, we designed a plain strategy for fabrication of the novel composite ZnO/CuCo₂O₄ and applied it as catalyst for peroxymonosulfate (PMS) activation to decompose enrofloxacin (ENR) under simulated sunlight. Compared to ZnO and CuCo₂O₄ alone, the ZnO/CuCo₂O₄ composite could significantly activate PMS under simulated sunlight, resulting in the generation of more active radicals for ENR degradation. Thus, 89.2 % of ENR could be decomposed over 10 min at natural pH. Furthermore, the influences of the experimental factors, including the catalyst dose, PMS concentration, and initial pH, on ENR degradation were evaluated. Subsequent active radical trapping experiments indicated that sulfate, superoxide, and hydroxyl radicals together with holes (h⁺) were involved in the degradation of ENR. Notably, the ZnO/CuCo₂O₄ composite exhibited good stability. Only 10 % decrease in ENR degradation efficiency was observed after four runs. Finally, several reasonable ENR degradation pathways were proposed, and the mechanism of PMS activation was elucidated. This study provides a novel strategy by integrating state-of-the-art material science and advanced oxidation technology for wastewater treatment and environmental remediation.

Electronic tuning of Ni-Fe-Co oxide/hydroxide as highly active electrocatalyst for rechargeable Zn-air batteries

As a bifunctional oxygen electrocatalyst (oxygen reduction reaction (ORR) and oxygen evolution reaction (OER)), spinel copper cobaltite (CuCo₂O₄) is attracting significant research interest owing to the tailored Co, Cu electronic structure and ease of adjusting the electrochemically active area. However, its poor OER performance (>300 mV at 10 mA cm^-2) limits its practical application for rechargeable zinc-air batteries. Therefore, we construct a CuCo₂O₄/NiFe LDH oxide/hydroxide interface to tune the properties of Ni, Fe and Co for enhancing OER activity and decreasing the charging overpotential of rechargeable zinc-air batteries. The obtained electrocatalysts show a low overpotential of 251 mV (10 mA cm^-2), which is 91 mV lower than the overpotential (342 mV) of CuCo₂O₄. By in situ Raman, XPS and electrochemical analyses, we ascribe the enhanced OER activity to the increasing Ni/Fe oxidation state triggered by the charge transfer of Ni/Fe and Co, which prompts CuCo₂O₄/NiFe LDH to rapidly form an active surface layer. Benefiting from enhanced OER performance, zinc-air batteries with a CuCo₂O₄/NiFe LDH electrode display a high round-trip efficiency with a low voltage gap of ∼0.78 V (10 mA cm^-2) due to the obvious decrease in the charging overpotential. These results suggest the importance of tuning the charge transfer on interfaces for designing high-efficiency electrocatalysts.

Nitrogen doped CuCo2O4 nanoparticles anchored on beaded-like carbon nanofibers as an efficient bifunctional oxygen catalyst toward zinc-air battery

The elaborative design and construction of first-rank bifunctional oxygen electrocatalysts featuring low price, high activity and strong stability is critical for the large-scale applications of rechargeable Zn-air batteries. Here, a resultful strategy is proposed for fabricating nitrogen-doped 1D beaded-like structure carbon nanofibers uniformly decorated with nitrogen-doped CuCo₂O₄ nanoparticles (N-CuCo₂O₄@CNFs) toward boosting oxygen evolution reaction/oxygen reduction reaction (OER/ORR) catalysis. Taking advantage of the synergistic effect between interconnected 1D hierarchical porous carbon nanofiber structure and high catalytic activity of N-doped CuCo₂O₄ nanoparticles derived from bimetallic MOFs, the N-CuCo₂O₄@CNFs catalysts possess enhanced reaction kinetics and preferable charge transfer ability. Impressively, the obtained catalysts exhibit prominent electrocatalytic ability and superior stability for OER/ORR, even surpass the commercial RuO₂ and Pt/C. More significantly, the Zn-air batteries employing the N-CuCo₂O₄@CNFs-800 as cathode display a higher power density of 175.6 mW cm^-2, a lower charge-discharge voltage gap of 0.82 V at 10 mA cm^-2, as well as a better cycling stability with respect to those of Pt/C + RuO₂ mixture, demonstrating the great potential of N-CuCo₂O₄@CNF as a high-efficiency catalyst for clean energy devices.

Ultrahigh-energy sodium ion capacitors enabled by the enhanced intercalation pseudocapacitance of self-standing Ti2Nb2O9/CNF anodes

In order to increase the capacity and improve the sluggish Na⁺-reaction kinetics of anodes as sodium ion capacitors (SICs), a Ti₂Nb₂O₉/CNF self-standing film electrode comprised of Ti₂Nb₂O₉ nanosheets and carbon nanofibers has been fabricated via electrospinning HTiNbO₅ nanosheets with PAN and subsequent carbonization treatment. The as-prepared Ti₂Nb₂O₉/CNF film electrode possesses fast Na-ion intercalation kinetics and high conductivity during Na-ion storage, and it displays a high reversible capacity of 324 mA h g^-1 at 0.1 A g^-1. Additionally, it also delivers a superior rate capability of 204 mA h g^-1 at a high current density of 4 A g^-1, as well as an excellent cycling stability of 97% retention after 2000 cycles at 1 A g^-1 in a half-cell test. A prototype Ti₂Nb₂O₉/CNF//AC SIC full device was assembled by employing the presodiated Ti₂Nb₂O₉/CNF anode and AC cathode, and it exhibits an high energy density of 129 W h kg^-1 at a power density of 75 W kg^-1 and a high power density (7560 W kg^-1 with 63 W h kg^-1), a good cycling performance of 85% capacitance retention after 10 000 cycles at 1 A g^-1, suggesting that the Ti₂Nb₂O₉/CNF electrode with excellent performance would be a very promising candidate as the anode for high-performance SICs.

Highly uniform platanus fruit-like CuCo2S4 microspheres as an electrode material for high performance lithium-ion batteries and supercapacitors

Platanus fruit-like CuCo₂S₄ microspheres were fabricated by using a facile hydrothermal method followed by a sulfidation process. As a lithium storage material, they deliver an outstanding initial specific capacity of 1119.3 mA h g^-1 at 0.05 A g^-1 and a high reversibility of 954 mA h g^-1 over 200 cycles even at 1 A g^-1. In addition, when applied in supercapacitors they display a superb specific capacitance of 824 F g^-1 at 1 A g^-1, even over 10 000 cycles and they can also maintain 75% retention at 5 A g^-1 and exhibit good reversibility. Furthermore, an advanced asymmetric supercapacitor (ASC) exhibits an advantageous energy density of 36.67 W h kg^-1 when the power density increases up to 750 W kg^-1. Additionally, the assembled device can easily light a 1.5 V bulb for several minutes. The excellent performance of CuCo₂S₄ is due to the bimetallic synergistic effect and the unique platanus fruit-like microsphere architecture, which can limit the restacking of the structure and provide suitable voids. This excellent performance confirms that platanus fruit-like CuCo₂S₄ microspheres are a promising electrode material for energy storge. This work will provide a new strategy to prepare high-performance bimetallic sulfide anode materials by a facile method.

Nitrogen-doped carbon encapsulated zinc vanadate polyhedron engineered from a metal-organic framework as a stable anode for alkali ion batteries

In this work, we fabricated vanadium/zinc metal-organic frameworks (V/Zn-MOFs) derived from self-assembled metal organic frameworks, to further disperse ultrasmall Zn₂VO₄ nanoparticles and encapsulate them in a nitrogen-doped nanocarbon network (ZVO/NC) under in situ pyrolysis. When employed as an anode for lithium-ion batteries, ZVO/NC delivers a high reversible capacity (807 mAh g^-1 at 0.5 A g^-1) and excellent rate performance (372 mAh g^-1 at 8.0 A g^-1). Meanwhile, when used in sodium-ion batteries, it exhibits long-term cycling stability (7000 cycles with 145 mAh g^-1 at 2.0 A g^-1). Additionally, when employed in potassium-ion batteries, it also shows outstanding electrochemical performance with reversible capacities of 264 mAh g^-1 at 0.1 A g^-1 and 140 mAh g^-1 at 0.5 A g^-1 for 1000 cycles. The mechanism by which the pseudocapacitive behaviour of ZVO/NC enhances battery performance under a suitable electrolyte was probed, which offers useful enlightenment for the potential development of anodes of alkali-ion batteries. The performance of Zn₂VO₄ as an anode for SIBs/PIBs was investigated for the first time. This work provides a new horizon in the design ZVO/NC as a promising anode material owing to the intrinsically synergic effects of mixed metal species and the multiple valence states of V.

Lithium-Ion Capacitors: A Review of Design and Active Materials

Lithium-ion capacitors (LICs) have gained significant attention in recent years for their increased energy density without altering their power density. LICs achieve higher capacitance than traditional supercapacitors due to their hybrid battery electrode and subsequent higher voltage. This is due to the asymmetric action of LICs, which serves as an enhancer of traditional supercapacitors. This culminates in the potential for pollution-free, long-lasting, and efficient energy-storing that is required to realise a renewable energy future. This review article offers an analysis of recent progress in the production of LIC electrode active materials, requirements and performance. In-situ hybridisation and ex-situ recombination of composite materials comprising a wide variety of active constituents is also addressed. The possible challenges and opportunities for future research based on LICs in energy applications are also discussed.

Suppressed Jahn-Teller Distortion in MnCo2 O4 @Ni2 P Heterostructures to Promote the Overall Water Splitting

Jahn-Teller distortion in cobalt based spinel electrocatalysts causes poor activity and stability in potentially promising catalysts for water splitting. Here, a novel strategy to resolve this problem by interface engineering is reported, in which, Jahn-Teller distortion in MnCo₂ O₄ is significantly suppressed by in situ growth Ni₂ P nanosheets onto the MnCo₂ O₄ . The significance of interface engineering in suppressing Jahn-Teller distortion of Mn³⁺ is further investigated by X-ray photoelectron spectroscopy, the resulting increased catalytic activity and the effects of suppressed distortion demonstrated by density functional theory calculations. The resulting MnCo₂ O₄ @Ni₂ P heterostructures exhibit superior electrocatalytic activity for the both oxygen evolution reaction and hydrogen evolution reaction with small overpotentials of 240 and 57 mV at 10 mA cm^-2 , respectively. Furthermore, the heterogeneous composite electrode demonstrates a superior current density of 10 mA cm^-2 at a voltage of 1.63 V with excellent durability in a water splitting cell.

Efficient Laser-Induced Construction of Oxygen-Vacancy Abundant Nano-ZnCo2 O4 /Porous Reduced Graphene Oxide Hybrids toward Exceptional Capacitive Lithium Storage

Recently, binary ZnCo₂ O₄ has drawn enormous attention for lithium-ion batteries (LIBs) as attractive anode owing to its large theoretical capacity and good environmental benignity. However, the modest electrical conductivity and serious volumetric effect/particle agglomeration over cycling hinder its extensive applications. To address the concerns, herein, a rapid laser-irradiation methodology is firstly devised toward efficient synthesis of oxygen-vacancy abundant nano-ZnCo₂ O₄ /porous reduced graphene oxide (rGO) hybrids as anodes for LIBs. The synergistic contributions from nano-dimensional ZnCo₂ O₄ with rich oxygen vacancies and flexible rGO guarantee abundant active sites, fast electron/ion transport, and robust structural stability, and inhibit the agglomeration of nanoscale ZnCo₂ O₄ , favoring for superb electrochemical lithium-storage performance. More encouragingly, the optimal L-ZCO@rGO-30 anode exhibits a large reversible capacity of ≈1053 mAh g^-1 at 0.05 A g^-1 , excellent cycling stability (≈746 mAh g^-1 at 1.0 A g^-1 after 250 cycles), and preeminent rate capability (≈686 mAh g^-1 at 3.2 A g^-1 ). Further kinetic analysis corroborates that the capacitive-controlled process dominates the involved electrochemical reactions of hybrid anodes. More significantly, this rational design holds the promise of being extended for smart fabrication of other oxygen-vacancy abundant metal oxide/porous rGO hybrids toward advanced LIBs and beyond.

Binder-Free Electrodes for Advanced Sodium-Ion Batteries

Sodium-ion batteries (SIBs) have recently emerged as one of the favored contenders for use in medium and large-scale stationary energy storage owing to the abundance of the resources required to fabricate them, their low cost, and the fact that have properties similar to equivalent Li batteries. However, their development also faces challenges such as poor cycling stability and unsatisfying rate performance. In traditional electrodes, binders are commonly used to integrate individual active materials with conductive additives. Unfortunately, binders are generally electrochemically inactive and insulating, which reduces the overall energy density and leads to poor cycling stability. Therefore, binder-free electrodes provide great opportunity for high-performance SIBs in terms of both improved electronic conductivity and electrochemical reaction reversibility. This Progress Report provides an overview of the recent progress in binder-free electrodes for SIBs. It focuses on the current challenges of binder-free electrodes and provides an outlook for their future in energy conversion and storage.

The construction of CuCo2O4/N-doped reduced graphene oxide hybrid hollow spheres as anodes for sodium-ion batteries

Hierarchical CuCo₂O₄/N-doped reduced graphene oxide (CuCo₂O₄/N-rGO) hollow hybrid nanospheres was constructed and further applied as highly capacity anode materials for SIBs.

Electrode Materials for High-Performance Sodium-Ion Batteries

Sodium ion batteries (SIBs) are being billed as an economical and environmental alternative to lithium ion batteries (LIBs), especially for medium and large-scale stationery and grid storage. However, SIBs suffer from lower capacities, energy density and cycle life performance. Therefore, in order to be more efficient and feasible, novel high-performance electrodes for SIBs need to be developed and researched. This review aims to provide an exhaustive discussion about the state-of-the-art in novel high-performance anodes and cathodes being currently analyzed, and the variety of advantages they demonstrate in various critically important parameters, such as electronic conductivity, structural stability, cycle life, and reversibility.

Controllable synthesis and electrochemical capacitor performance of MOF-derived MnOx/N-doped carbon/MnO2 composites

Different amount of carbon and nitrogen, for MOF-derived nitrogen-doped carbon/Mn₃O₄ composites, can result in the discrepancies of synergistic effect which plays an important role in final electrochemical performance.

The transformation of anatase TiO2 to TiSe2 to form TiO2–TiSe2 composites for Li+/Na+ storage with improved capacities

We discovered and explored the basic conditions for the conversion of TiO₂-A to TiSe₂ and tested its electrochemical performance.

Amorphous cobalt–iron hydroxides as high-efficiency oxygen-evolution catalysts based on a facile electrospinning process

The first example of amorphous CoFe hydroxide based on the electrospinning process was developed, which was used as an efficient OER catalyst.

Recent Advances in Nanowire-Based, Flexible, Freestanding Electrodes for Energy Storage

The rational design of flexible electrodes is essential for achieving high performance in flexible and wearable energy-storage devices, which are highly desired with fast-growing demands for flexible electronics. Owing to the one-dimensional structure, nanowires with continuous electron conduction, ion diffusion channels, and good mechanical properties are particularly favorable for obtaining flexible freestanding electrodes that can realize high energy/power density, while retaining long-term cycling stability under various mechanical deformations. This Minireview focuses on recent advances in the design, fabrication, and application of nanowire-based flexible freestanding electrodes with diverse compositions, while highlighting the rational design of nanowire-based materials for high-performance flexible electrodes. Existing challenges and future opportunities towards a deeper fundamental understanding and practical applications are also presented.

1D Sub-Nanotubes with Anatase/Bronze TiO2 Nanocrystal Wall for High-Rate and Long-Life Sodium-Ion Batteries

The development of 1D nanostructures with enhanced material properties has been an attractive endeavor for applications in energy and environmental fields, but it remains a major research challenge. Herein, this work demonstrates a simple, gel-derived method to synthesize uniform 1D elongated sub-nanotubes with an anatase/bronze TiO₂ nanocrystal wall (TiO₂ SNTs). The transformation mechanism of TiO₂ SNTs is studied by various ex situ characterization techniques. The resulting 1D nanostructures exhibit, synchronously, a high aspect ratio, open tubular interior, and anatase/bronze nanocrystal TiO₂ wall. This results in excellent properties of electron/ion transport and reaction kinetics. Consequently, as an anode material for sodium-ion batteries (SIBs), the TiO₂ SNTs display an ultrastable long-life cycling stability with a capacity of 107 mAh g^-1 at 16 C after 4000 cycles and a high-rate capacity of 94 mAh g^-1 at 32 C. This a high-rate and long-life performance is superior to any report on pure TiO₂ for SIBs. This work provides new fundamental information for the design and fabrication of inorganic structures for energy and environmental applications.

Enhanced electrochemical properties of SnO2-graphene-carbon nanofibers tuned by phosphoric acid for potassium storage

Potassium-ion batteries (KIBs) are considered as attractive alternatives to commercial lithium-ion batteries. However, the lack of suitable electrodes to host large K⁺ for rapid as well as reversible insertion/extraction hinders the developments of KIBs. As an attempt, the phosphoric acid doped SnO₂-graphene-carbon (P-SGC) nanofibers synthesized with a facile electrospinning method are introduced and applied as anode materials for KIBs. The P-SGC anodes present a reversible capacity of 285.9 mAh g^-1 over 60 cycles at the current density of 100 mA g^-1, and the high rate capacity of 208.53 mAh g^-1 at 1 A g^-1 as well. Emphasis is placed on enhancing the electrochemical properties of the SGC nanofibers by phosphoric acid modification through more active sites and higher electrical conductivity, accounting for improved K⁺ diffusion kinetics. Meanwhile, the coated carbon matrix and dispersive graphene buffer the structural changes and protect the active materials from destruction, leading to the good structural stability. With the presented results, these P-SGC nanofibers show attractive potential for future energy storage application of KIBs.

Porous NaTi2(PO4)3/C Hierarchical Nanofibers for Ultrafast Electrochemical Energy Storage

NaTi₂(PO₄)₃ (NTP) with a sodium superionic conductor three-dimensional (3D) framework is a promising anode material for sodium-ion batteries (SIBs) because of its suitable potential and stable structure. Although its 3D structure enables high Na-ion diffusivity, low electronic conductivity severely limits NTP's practical application in SIBs. Herein, we report porous NTP/C nanofibers (NTP/C-NFs) obtained via an electrospinning method. The NTP/C-NFs exhibit a high reversible capacity (120 mA h g^-1 at 0.2 C) and a long cycling stability (a capacity retention of ∼93% after 700 cycles at 2 C). Furthermore, sodium-ion full cells and hybrid sodium-ion capacitors have also been successfully assembled, both of which exhibit high-rate capabilities and remarkable cycling stabilities because of the high electronic/ionic conductivity and impressive structural stability of NTP/C-NFs. The results show that the nanoscale-tailored NTP/C-NFs could deliver new insights into the design of high-performing and highly stable anode materials for room-temperature SIBs.

Rational Design of Co(II) Dominant and Oxygen Vacancy Defective CuCo2O4@CQDs Hollow Spheres for Enhanced Overall Water Splitting and Supercapacitor Performance

The hierarchical CuCo₂O₄@carbon quantum dots (CQDs) hollow microspheres constructed by 1D porous nanowires have been successfully prepared through a simple CQDs-induced hydrothermal self-assembly technique. XPS analysis shows the CuCo₂O₄@CQDs possesses the Co(II)-rich surface associated with the oxygen vacancies, which can effectively boost the Faradaic reactions and oxygen evolution reaction (OER) activity. For example, the as-synthesized 3D porous CuCo₂O₄@CQDs electrode exhibits high activity toward overall electrochemical water splitting, for example, an overpotential of 290 mV for OER and 331 mV for hydrogen evolution reaction (HER) in alkaline media have been achieved at 10 mA cm^-2, respectively. Furthermore, an asymmetric supercapacitor (ASC) (CuCo₂O₄@CQDs//CNTs) delivers a high energy density of 45.9 Wh kg^-1 at 763.4 W kg^-1, as well as good cycling ability. The synergy of Co(II)-rich surface, oxygen vacancies, and well-defined 3D hollow structures facilitates the subsequent surface electrochemical reactions. This work presents a facile method to fabricate energetic nanocomposites with highly reactive, durable, and universal functionalities.

Ultrasmall TiO2-Coated Reduced Graphene Oxide Composite as a High-Rate and Long-Cycle-Life Anode Material for Sodium-Ion Batteries

Because of the low cost and abundant nature of the sodium element, sodium-ion batteries (SIBs) are attracting extensive attention, and a variety of SIB cathode materials have been discovered. However, the lack of high-performance anode materials is a major challenge of SIBs. Herein, we have synthesized ultrasmall TiO₂-nanoparticle-coated reduced graphene oxide (TiO₂@RGO) composites by using a one-pot hydrolysis method, which are then investigated as anode materials for SIBs. The morphology of TiO₂@RGO has been characterized using transmission electron microscopy, indicating that the TiO₂ nanospheres uniformly grow on the surface of the RGO nanosheet. As-prepared TiO₂@RGO composites exhibited a promising electrochemical performance in terms of cycling stability and rate capability, especially the initial cycle Coulombic efficiency of 60.7%, which is higher than that in previous reports. The kinetics of the electrode reaction has been investigated by cyclic voltammetry. The results indicate that the sodium-ion intercalation/extraction behavior is not controlled by the semiinfinite diffusion process, which gives rise to an outstanding rate performance. In addition, the electrochemical performance of TiO₂@RGO composites in full cells, coupled with carbon-coated Na₃V₂(PO₄)₃ as the positive material, has been investigated. The discharge specific capacity was up to 117.2 mAh g^-1, and it remained at 84.6 mAh g^-1 after 500 cycles under a current density of 2 A g^-1, which shows excellent cycling stability.

1D Nanomaterials: Design, Synthesis, and Applications in Sodium-Ion Batteries

Sodium-ion batteries (SIBs) have received extensive attention as ideal candidates for large-scale energy storage systems (ESSs) owing to the rich resources and low cost of sodium (Na). However, the larger size of Na⁺ and the less negative redox potential of Na⁺ /Na result in low energy densities, short cycling life, and the sluggish kinetics of SIBs. Therefore, it is necessary to develop appropriate Na storage electrode materials with the capability to host larger Na⁺ and fast ion diffusion kinetics. 1D materials such as nanofibers, nanotubes, nanorods, and nanowires, are generally considered to be high-capacity and stable electrode materials, due to their uniform structure, orientated electronic and ionic transport, and strong tolerance to stress change. Here, the synthesis of 1D nanomaterials and their applications in SIBs are reviewed. In addition, the prospects of 1D nanomaterials on energy conversion and storage as well as the development and application orientation of SIBs are presented.

Anchoring CoFe2O4 Nanoparticles on N-Doped Carbon Nanofibers for High-Performance Oxygen Evolution Reaction

The exploration of earth-abundant and high-efficiency electrocatalysts for the oxygen evolution reaction (OER) is of great significant for sustainable energy conversion and storage applications. Although spinel-type binary transition metal oxides (AB2O4, A, B = metal) represent a class of promising candidates for water oxidation catalysis, their intrinsically inferior electrical conductivity exert remarkably negative impacts on their electrochemical performances. Herein, we demonstrates a feasible electrospinning approach to concurrently synthesize CoFe2O4 nanoparticles homogeneously embedded in 1D N-doped carbon nanofibers (denoted as CoFe2O4@N-CNFs). By integrating the catalytically active CoFe2O4 nanoparticles with the N-doped carbon nanofibers, the as-synthesized CoFe2O4@N-CNF nanohybrid manifests superior OER performance with a low overpotential, a large current density, a small Tafel slope, and long-term durability in alkaline solution, outperforming the single component counterparts (pure CoFe2O4 and N-doped carbon nanofibers) and the commercial RuO2 catalyst. Impressively, the overpotential of CoFe2O4@N-CNFs at the current density of 30.0 mA cm-2 negatively shifts 186 mV as compared with the commercial RuO2 catalyst and the current density of the CoFe2O4@N-CNFs at 1.8 V is almost 3.4 times of that on RuO2 benchmark. The present work would open a new avenue for the exploration of cost-effective and efficient OER electrocatalysts to substitute noble metals for various renewable energy conversion/storage applications.

Carbon Derived from Pine Needles as a Na+-Storage Electrode Material in Dual-Ion Batteries

Pine needles are used as the precursor material to prepare hard carbon. Scanning electron microscopy, X-ray diffraction, and N2 adsorption-desorption tests are carried out to characterize the surface, crystal, and pore structure of the material. The pine needle derived carbon (PNC) exhibits excellent Na-ion storage ability. A dual-ion battery of PNC/graphite using a Na+-based organic electrolyte is constructed. The batteries display outstanding electrochemical performance: a superior energy density (200 Wh kg-1 at 131 W kg-1), high cut-off voltage (4.7 V), and outstanding cycling stability (87.2% retention after 1000 cycles). In addition, the separate responses of the cathode and anode are investigated.

Novel iodine-doped reduced graphene oxide anode for sodium ion batteries

It is reported for the first time that iodine-doped reduced graphene oxide (I-rGO) has been designed as an anode material for sodium ion batteries (SIBs).