High Rate Performance Research Articles

Ternary Lithium Nickel Boride with 1D Rapid-Ion-Diffusion Channels as an Anode for Use in Lithium-Ion Batteries.

Anode materials with high-rate performances and good electrochemical stabilities are urgently required for the grid-scale application of lithium-ion batteries (LIBs). Theoretically, transition metal borides are desirable candidates because of their appropriate working potentials and good conductivities. However, the reported metal borides exhibit poor performances owing to their lack of favorable Li+ storage sites and poor structural stabilities during long-term charging/discharging. In this work, a ternary alkali metal boride, Li1.2Ni2.5B2, which displays a high Li+ storage capacity and remarkable electrochemical stability and an excellent rate performance is studied. In contrast to conventional transition metal borides, the introduction of Li atoms facilitates the formation of 1D Ni/B-based honeycomb channels during synthesis. This Ni/B framework successfully sustains the strain during Li+ intercalation and deintercalation, and thus, the optimized Li1.2Ni2.5B2 anode exhibits an excellent cycle stability over 500 charge/discharge cycles. This electrode also exhibits superior reversible capacities of 350, 183, and 80mAhg-1 at 0.1, 1, and 5Ag-1, respectively, indicating the considerable potential of the 1D Ni/B framework as a commercially available fast-charging LIB anode.

Assessing the impact of center volume on the cost-effectiveness of centralizing ERCP

Background and AimsERCP is a complex endoscopic procedure in which the center's procedure volume influences outcomes. With the increasing healthcare expenses and limited resources, promoting cost-effective care becomes essential for healthcare provision. This study performed a cost-effectiveness analysis to evaluate the hypothesis that high-volume (HV) centers perform ERCP with higher quality at lower costs than low-volume (LV) centers. MethodsA baseline case compared the current distribution of ERCPs among HV and LV centers with a hypothetical scenario in which all ERCPs are performed at HV centers. A cost-effectiveness analysis was constructed, followed by one-way and two-way sensitivity analyses and probabilistic sensitivity analysis (PSA) using Monte Carlo simulations. ResultsIn the baseline case, the ICER was -141,017€/year, due to the hypothetical scenario's lower costs and slightly higher QALYs. The model was most sensitive to changes in the transportation costs (109.34%), probability of significant adverse events (AEs) after successful ERCP at LV centers (42.12%), utility after ERCP with significant AEs (30.10%), and probability of significant AEs after successful ERCP at HV centers (23.53%) but only transportation cost above 3,407€ changed the study outcome. The current ERCP distribution would only be cost-effective if LV centers achieved higher success (≥ 92.4% vs. 89.3%) with much lower significant AEs (≤ 0.5% vs 6.7%). The study's main findings remained unchanged while combining all model parameters in the PSA. ConclusionsOur findings show that HV centers have high-performance rates at lower costs, raising the need to consider the principle of centralization of ERCPs into HV centers to improve the quality of care.

High-rate performance of Li–S/Na–S batteries achieved by C/Sn composites with high active Sn atoms

Li–S batteries and Na–S batteries attract wide attention because of high specific capacity, rich resources and environmental friendliness, but poor rate performance limits their development. Single atoms perform as active sites and promote redox reaction process of sulfur, which are benefit for improving rate performance of Li–S batteries and Na–S batteries. However, many researches only focus on transition metal atoms instead of non-transition metal atoms. Sn atoms are introduced on carbon surface to obtain C/Sn composites and electrochemical performance of C/Sn/S composites in Li–S batteries and Na–S batteries is studied in this paper. As for comparison, electrochemical performance of C/S without Sn atom modified is also studied. Results show that C/Sn/S composite electrodes possess higher rate performance than C/S composite electrodes in both Li–S batteries (359 mAh·g−1 at 20C) and Na–S batteries (151 mAh·g−1 at 20C). High-rate performance of C/Sn/S composite electrodes in Li–S batteries is attributed to catalytic abilities of active Sn atoms and high conductivity of carbon. Researches provide references for structure control and application of carbon composites with non-transition metal atom modified.

Dual‐Stroke Soft Peltier Pouch Motor Based on Pipeless Thermo‐Pneumatic Actuation

Soft pneumatic actuators are made of flexible materials that deform in response to pressure changes. Due to their reliability, safety, and flexibility, such actuators enable diverse hardware design and become indispensable for soft robots. However, bulky air compressors and pipes constrain their further integration and lightweight. The liquid–vapor phase transition can produce significant encapsulated volume changes and achieve pipeless thermo‐pneumatic actuation. Herein, a novel soft thermoelectric‐based actuator, named Peltier pouch motor (PPM), is presented with modular and dual‐stroke characteristics enabled by active phase transition of low‐boiling‐point liquid. Furthermore, its lightweight and stretchable compliance contributes to assembly‐induced hyper‐modularity to create diverse degrees‐of‐freedom hybrid systems. Finally, the various forms of PPM units are exploited and versatile locomotion is facilitated for five different applications under multi‐medium scenarios, including thermo‐responsive land locomotion, submersible noise‐free hovering, smart curtains control, body‐temperature‐driven wrist rehabilitation, and adaptive hybrid gripper. In these results, it is indicated that the proposed PPM unit advances in hyper‐modularity with excellent performance in high load rate (around 400%), heat transfer efficiency (heating boost, 425%; cooling boost, 138%), and thermal response performance (heating, 0.57° s−1; cooling, 0.29° s−1; 4.5 V), inspiring widely innovative soft robots through the pipeless thermo‐pneumatic actuation.

Facile preparation of Ni@C/hierarchically porous carbon nanocomposites with excellent electrochemical performance from Ni-MOF/porous polymers

High performance supercapacitors are significant for the practical application of the novel renewable energies. Comparisons suggest that hybrid supercapacitor (HSC) is a fairly promising type for application since it combines high power density and high energy density. In this study, hierarchically porous carbons (HPCs) supported Ni@C nanoparticles (Ni@C/HPCs) were obtained by pyrolyzing the precursors of Ni-based MOF/porous polymers (Ni-MOF/polyHIPEs) which were prepared by high internal phase emulsion (HIPE) polymerization followed with solvothermal Ni-MOF growing. The composition and morphology of the Ni@C/HPCs can be controlled by changing the growth time of Ni-MOF. The optimized sample Ni@C/HPC-15 demonstrates a high specific capacity of 215.0 C g−1 at 1 A g−1 and a high rate performance of 82.3% when the current density increases from 1 A g−1 to 10 A g−1. Furthermore, Ni@C/HPC//HPC HSC was assembled and achieved an energy density of 40.9 Wh kg−1 at a power density of 747.2 W kg−1. In particular, the assembled HSC exhibited a remarkable initial capacitance retention of 86.3% after 5000 cycles at 6 A g−1. The reported convenient method may provide inspiration in the preparation and optimization of HPC-based electrode materials with satisfactory performances for energy storage.

Interlayer engineering and electronic regulation of MoSe2 nanosheets rolled hollow nanospheres for high-performance sodium-ion half/full batteries

Layered transition metal dichalcogenides are promising candidates for sodium storage but suffering from low intrinsic electronic conductivity and limited interlayer spacing for fast electron/ion transport, which restricts their high-rate capability and cycling stability. In this work, rGO@MoSe2/NAC hierarchical architectures, consisting of conductive reduced graphene oxide (rGO) supported by hollow nanospheres that are rolled from superlattices of alternatively overlapped MoSe2 and N-doped amorphous carbon (NAC) monolayers, are synthesized as a high-performance sodium storage anode. Theoretical calculations reveal the intercalation of NAC monolayer between two adjacent MoSe2 monolayers improving electronic conductivity of MoSe2 in both surface and internal bulk to fully accelerate electron transport and enhance Na+ ​adsorption. The interoverlapped MoSe2/NAC superlattice featuring a wide interlayer expansion (72.3 ​%) of MoSe2 dramatically decreases Na+ ​diffusion barriers for fast insertion/extraction. Moreover, the hollow nanospheres and the rGO conductive network contribute to a robust hiberarchy that can well release internal stress and buffer the volume expansion, thereby enabling outstanding structural stability. Consequently, the rGO@MoSe2/NAC anode exhibits excellent high-rate capability of 194 mAh g−1 and ultralong cyclability of 12 ​000 cycles with a low capacity fading rate of 0.0038 ​% per cycle at an ultra-high current of 50 ​A ​g−1, delivering the best high-rate cycling performance to date. Remarkably, the Na3V2(PO4)3‖rGO@MoSe2/NAC full cells also present outstanding cycling stability (600 cycles) at 10C rate, which proves the great potential in fast-charging applications.

Amphipathic Janus Nanofibers Aerogel for Efficient Solar Steam Generation

Solar steam generation is a promising water purification technology due to its low‐cost and environmentally friendly applications in water purification and desalination. However, hydrophilic or hydrophobic materials alone are insufficient in achieving necessary characteristics for constructing high‐quality solar steam generators with good comprehensive properties. Herein, novel hydrophile/hydrophobe amphipathic Janus nanofibers aerogel is designed and used as a host material for preparing solar steam generators. The product consists of an internal cubic aerogel and an external layer of photothermal materials. The internal aerogel is composed of electrospun amphipathic Janus nanofibers. Owing to the unique composition and structure, the prepared solar steam generator integrates the features of high water evaporation rate (2.944 kg m−2 h−1 under 1 kW m−2 irradiation), self‐floating, salt‐resisting, and fast performance recovery after flipping. Moreover, the product also exhibits excellent properties on desalination and removal of organic pollutants. Compared with traditional hydrophilic aerogel host material, the amphipathic Janus nanofibers aerogel brings much higher water evaporation rate and salt resistance.

Porous N-Doped Carbon Decorated with Atomically Dispersed Independent Dual Metal Sites from Energetic Zeolite Imidazolate Frameworks as Bidirectional Catalysts for Lithium-Sulfur Batteries.

Lithium-sulfur (Li-S) batteries have ultrahigh theoretical specific capacity and energy density, which are considered to be very promising energy storage devices. However, the slow redox kinetics of polysulfides are the main reason for the rapid capacity decay of Li-S batteries. A reasonable electrocatalyst for the Li-S battery should reduce the reaction barrier and accelerate the reaction kinetics of the bidirectional catalytic conversion of lithium polysulfides (LiPSs), thereby reducing the cumulative concentration of LiPSs in the electrolyte. In this report, porous N-doped carbon nanofibers decorated with independent dual metal sites as catalysts for Li-S batteries were fabricated in one step using a fusion-foaming method. Experimental and theoretical analyses demonstrate that the synergistic effect of independent dual metal sites provides strong LiPS affinity, improved electronic conductivity, and enhanced redox kinetics of polysulfides. Therefore, the assembled Li-S battery exhibits high rate performance (discharge specific capacity of 771 mA h g-1 at 2C) and excellent cycle stability (capacity decay rate of 0.51% after 1000 cycles at 1C).

Construction of ultrastable and high-rate performance zinc anode with three-dimensional porous structure and Schottky contact

The artificial interface layer on the Zn anode can effectively suppress by-product formation and dendrite growth, playing a crucial role in achieving high-rate and long-life aqueous zinc-ion batteries. However, the current galvanizing mode, where plating occurs separately below or inside the interface layer after its introduction, poses risks of detachment or swelling during cycling, limiting practical applications. In this study, we fabricate a three-dimensional porous NiO interface layer with enhanced anode dynamics that forms a Schottky contact with the zinc substrate. Through the synergistic effect of this excellent structure and Schottky barrier, zinc is rapidly and uniformly plated both inside and below the interface layer simultaneously. Symmetrical cells based on NiO@Zn exhibit exceptional stability over 10,000 cycles at an ultrahigh current density of 20 mA cm−2. Furthermore, NiO@Zn||MnO2 full cells deliver a capacity of 228 mAh g−1 and retain 94% of their initial capacities for 500 cycles at a density of 1 A g−1. This work not only presents highly reversible zinc anodes but also proposes an innovative galvanizing model.

All‐in‐one Biomass‐Based Flexible Supercapacitors with High Rate Performance and High Energy Density

AbstractTaking advantage of the unique structure and properties of gramineous straw that are available across the world in a yearly scale of several hundred million tons, a strategy to design and fabricate flexible high‐performance supercapacitors (SCs) is developed, of which the key components including electrode, separator, and electrolyte are all made from the eulaliopsis binata (EB), a ubiquitous gramineous straw. This kind of all‐in‐one biomass‐based flexible supercapacitors (BFSs) is first proposed, with the cuticle‐derived fibers (EBMs) as a separator, the pith‐derived carbon sponges (EBCs) as an electrode, and the sodium salts of the extracted carboxymethyl cellulose as gel electrolyte. The EBM with uniform diameter size, developed porosity, and abundant ‐OH/‐COOH groups have good flexibility, wettability, and ionic conductivity, far exceeding those of commercial glass‐fiber separators. The EBC has a high level of N/O/S co‐doping and hierarchical porous structure, resulting in enhanced ion accessibility and supercapacitance. With these advantages, the as‐fabricated BFS has shown ultra‐high‐rate performance, high energy density, and excellent flexibility, surpassing the biomass‐derived flexible supercapacitors reported thus far. This novel approach will shed light on the value‐added utilization of biomass from the viewpoint of molecular chemical engineering and product engineering and pave the way for fabricating flexible high‐performance SCs and beyond.

Human Movement Recognition Based on 3D Point Cloud Spatiotemporal Information from Millimeter-Wave Radar

Human movement recognition is the use of perceptual technology to collect some of the limb or body movements presented. This practice involves the use of wireless signals, processing, and classification to identify some of the regular movements of the human body. It has a wide range of application prospects, including in intelligent pensions, remote health monitoring, and child supervision. Among the traditional human movement recognition methods, the widely used ones are video image-based recognition technology and Wi-Fi-based recognition technology. However, in some dim and imperfect weather environments, it is not easy to maintain a high performance and recognition rate for human movement recognition using video images. There is the problem of a low recognition degree for Wi-Fi recognition of human movement in the case of a complex environment. Most of the previous research on human movement recognition is based on LiDAR perception technology. LiDAR scanning using a three-dimensional static point cloud can only present the point cloud characteristics of static objects; it struggles to reflect all the characteristics of moving objects. In addition, due to its consideration of privacy and security issues, the dynamic millimeter-wave radar point cloud used in the previous study on the existing problems of human body movement recognition performance is better, with the recognition of human movement characteristics in non-line-of-sight situations as well as better protection of people’s privacy. In this paper, we propose a human motion feature recognition system (PNHM) based on spatiotemporal information of the 3D point cloud of millimeter-wave radar, design a neural network based on the network PointNet++ in order to effectively recognize human motion features, and study four human motions based on the threshold method. The data set of the four movements of the human body at two angles in two experimental environments was constructed. This paper compares four standard mainstream 3D point cloud human action recognition models for the system. The experimental results show that the recognition accuracy of the human body’s when walking upright can reach 94%, the recognition accuracy when moving from squatting to standing can reach 84%, that when moving from standing to sitting can reach 87%, and the recognition accuracy of falling can reach 93%.

Boosting the cycling and storage performance of lithium nickel manganese cobalt oxide-based high-rate batteries through cathode manipulation

Lithium Nickel Manganese Cobalt Oxide (NCM) is extensively employed as promising cathode material due to its high-power rating and energy density. However, there is a long-standing vacillation between conventional polycrystalline and single-crystal cathodes due to their differential performances in high-rate capability and cycling stability. Herein, a complexing strategy is proposed based on the investigation of capacity fading mechanism of both polycrystalline and single crystal NCM. A series of mixed cathodes containing both types of NCM particles with different mass ratio have been compared. The optimized NCM-37 cathode realized a balance between high-rate performances, high-temperature storage, and stable cycling. Specifically, the NCM-37 sustains a capacity retention of 98.4% after 300 cycles under 1 C charge/30 C discharge. Moreover, after storage at 60°C for 7 days, the capacity retention and recovery ratio are 91.73% and 95.02%, respectively. This work demonstrates an efficient approach to improve the comprehensive performances of prototype lithium-ion batteries by cathode manipulation, which can fully utilize the advantages and suppress the disadvantages of conventional polycrystalline and single crystal NCM particles.

Precise Tuning of Hollow and Pore Size of Bimetallic MOFs Derivate to Construct High-Performance Nanoscale Materials for Supercapacitors and Sodium-Ion Batteries.

Precise control of pore volume and size of carbon nanoscale materials is crucial for achieving high capacity and rate performances of charge/discharge. In this paper, starting from the unique mechanism of the role of In, Zn combination, and carboxyl functional groups in the formation of the lumen and pore size, the composition of InZn-MIL-68 is regulated to precisely tune the diameter and wall pore size of the hollow carbon tubes. The hollow carbon nanotubes (CNT) with high-capacity storage and fast exchange of Na+ ions and charges are prepared. The CNT possess ultra-high specific capacitance and ultra-long cycle life and also offer several times higher Na+ ion storage capacity and rate performance than the existing CNTs. Density functional theory calculations and tests reveal that these superior characteristics are attributed to the spacious hollow structure, which provides sufficient space for Na+ storage and the tube wall's distinctive porosity of tube wall as well as open ends for facilitating Na+ rapid desorption. It is believed that precise control of sub-nanopore volume and pore size by tuning the composition of the carbon materials derived from bimetallic metal-organic frameworks (MOFs)will establish the basis for the future development of high-energy density and high-power density supercapacitors and batteries.

A Catalytic Electrolyte Additive Modulating Molecular Orbital Energy Levels of Lithium Polysulfides for High-Performance Lithium-Sulfur Batteries.

Lithium-sulfur (Li-S) batteries have ultrahigh theoretical specific capacity, but the practical application is hindered by the severe shuttle effect and the sluggish redox kinetics of the intermediate lithium polysulfides (LiPSs). Effectively enhancing the conversion kinetics of LiPSs is essential for addressing these issues. Herein, the redox kinetics of LiPSs are effectively improved by introducing 6-azauracil (6-AU) molecules to the organic electrolyte to modulate the molecular orbital energy level of LiPSs. The 6-AU as a soluble catalyst can form complexes with LiPSs via Li-O bonds. These complexes are liable to transform because of the elevated HOMO and the reduced LUMO energy levels as compared to the dissociative LiPSs, resulting in small energy gaps (Egap) and exhibiting stronger redox activity. Benefiting from the rapid conversion kinetics, the shuttling effect of LiPSs is alleviated to a great extent, so that sulfur utilization is improved and the lithium electrode is protected. In addition, the introduction of 6-AU modulates the deposition behavior of Li2S and eases the coverage of the cathode surface by the insulating Li2S layer. The Li-S battery containing 6-AU provides superior capacity retention of 853 mAh g-1 after 150 cycles at 0.2 C and shows remarkable high-rate performance and retains a specific discharge capacity of 855 mAh g-1 at 5 C. This study accelerates the kinetics of Li-S batteries by tuning the HOMO and LUMO energy levels of LiPSs, which opens an avenue for designing functional electrolyte additives.

Honeycomb nanoarchitectonics of MnO2/carbon-confined Fe(CN)63− electrode for high capacitance and rate performance based on EDLC and dual-pseudocapacitance

MnO2, a pseudocapacitive material, is considered an important component to fabricate electrodes for aqueous supercapacitors. However, the poor conductivity and low specific capacitance (<250 F g−1) of MnO2 become roadblocks on the way to its more applications. Here, we demonstrate the possibility of preparing a high-performance MnO2-based electrode (OPHC-MnO2-K3Fe(CN)6) with MnO2/honeycomb carbon-confined K3Fe(CN)6. The vertically aligned MnO2 nanosheets are tightly immobilized on the OPHC surface and Fe(CN)63− adsorbs on OPHC-MnO2 interface, which ensure electrons are rapidly transported between multiple interfaces during the redox couples of Mn(IV)/Mn(III) and Fe(CN)63−/Fe(CN)64−. The OPHC-MnO2-K3Fe(CN)6 electrode exhibits not only electric double-layer capacitance but also pseudocapacitance derived from the redox couples of Mn(IV)/Mn(III) and Fe(CN)63−/Fe(CN)64−, thus presenting both high capacitance and rate (332.7 and 141.1 F g−1 at 0.5 and 100 A g−1, respectively). More importantly, the assembled OPHC-MnO2-K3Fe(CN)6//OPHC-K3Fe(CN)6 asymmetric supercapacitor provides a remarkable energy density of 75.6 Wh kg−1 at a power density of 302.2 W kg−1 and an outstanding cycling performance reflected by the capacitance retention of 99.6 % after 20,000 cycles. Our research opens a new avenue for designing and synthesizing versatile pseudocapacitive materials with high performance.

In-situ generated elemental selenium nanograins cooperated with NiSe2 microspheres for significantly enhanced magnesium-storage performance

Rechargeable magnesium batteries (RMBs) are advantageous for large-scale energy storage applications, but their development is hindered by lack of cathode materials. Conversion-type compounds or elemental Se materials break the limit of intercalation mechanism and provide more selections with high capacities. However, conversion compounds often show low reaction reversibility and elemental Se suffers from serious dissolution of polyselenides. Herein, a new strategy of binary selenide/elemental Se is developed to design RMB cathodes. A NiSe2/Se composite was fabricated by selenization of the Ni-MOF precursor, with Se uniform distribution in the NiSe2 microspheres. The elemental Se not only provides extra capacity but also improves the conversion reversibility of NiSe2. Furthermore, the NiSe2 microspheres confine polyselenides, significantly optimizing the cycleability of elemental Se. The NiSe2/Se electrode shows a reversible capacity of 211 mAh/g at 50 mA g−1, a high rate performance of 104 mAh/g at 1.0 A/g, as well as a stable capacity of 132 mAh/g at 200 mA g−1 (retention rate of 80.3 %) after 300 cycles. A mechanism study confirms that both of NiSe2 and Se undergo reversible conversion reaction with Mg2+. The binary selenide/elemental Se cooperative strategy herein delivers a new insight into the exploration of high-performance RMB cathodes.

Synthesis of 2D bi-metallic Zn/Cu metal-organic framework integrated graphene nanocomposites for all-solid-state asymmetric supercapacitors

In this work, a novel two-dimensional (2D) bi-metallic metal-organic frameworks (MOFs) consisting of zinc and copper metal centers with 1,3,5-tricarboxylic acid as a chief and efficient organic linker (Zn/Cu-BTC) and its composite with exfoliated graphene nanosheets (EGNSs) have been investigated for supercapacitor applications. The composites were synthesized via facile in-situ solvothermal process. Different spectroscopic, microscopic, and surface analyses confirmed the successful formation of porous electroactive composites, where 2D MOF nanosheets were vertically grown on the EGNS surfaces. In the two-electrode symmetric system, the as-synthesized Zn/Cu-BTC MOF@EGNS electrode achieved an enhanced specific gravimetric capacitance and equivalent volumetric capacitance of 1284.9 F/g and 813.3 F/cm3 at 0.5 A/g. It exhibits high-rate performance and prolonged cycling stability with >90 % retention after 8000 cycles. All-solid-state asymmetric supercapacitor (ASC) device was constructed with Zn/Cu-BTC MOF@EGNS composite and EGNS electrodes, where PVA-KOH membrane served as a separator-cum-electrolyte. The ASC device delivered a satisfactory energy density of 60.55 Wh kg−1 and a maximum power density of 10 kW kg−1 with an admirable cycling stability of 92 % after 10,000 charge-discharge cycles. In the future, this work can encourage manufacturing innovation.

A mixed dual-ion electrolyte for high-rate performance and remarkable cycling stability of NaMnO2 in hybrid supercapacitors

Recently, pre-sodiated manganese oxides are gaining more attention due to their higher specific capacitance and better cycling stability compared to pristine manganese oxides. However, previous reports on their electrochemical performances are limited to the aqueous electrolytes of Na+ and K+ ions. In this study, the electrochemical capacitance properties of hydrothermally synthesized NaMnO2 are investigated in aqueous electrolytes of 0.5 M NaNO3, 0.5 M Mg(NO3)2, and the mixed dual-ion electrolyte of 0.5 M NaNO3 and 0.25 M Mg(NO3)2. Although 0.5 M Mg(NO3)2 enables a higher specific capacitance of 427 F g−1 compared to that of 267 F g−1 in NaNO3 electrolyte, both electrolytes provide limited rate capability. On the other hand, the mixed dual-ion electrolyte of 0.5 M NaNO3+0.25 M Mg(NO3)2 enables highly improved rate capability along with a high specific capacitance of 325 F g−1, signifying the importance of the mixed dual-ion electrolyte for optimizing the specific capacitance and the high-rate capability of NaMnO2. An aqueous hybrid supercapacitor of activated carbon||NaMnO2 demonstrates excellent cycling stability of 98.9 % capacitance retention in the mixed electrolyte as compared to 96.9 % in NaNO3 electrolyte after 6000 cycles.

Ultrafast and ultrastable FeSe2 embedded in nitrogen-doped carbon nanofibers anode for sodium-ion half/full batteries

Transition metal selenides are considered as promising anode materials for fast-charging sodium-ion batteries due to their high theoretical specific capacity. However, the low intrinsic conductivity, particle aggregation, and large volume expansion problems can severely inhibit the high-rate and long-cycle performance of the electrode. Herein, FeSe2 nanoparticles embedded in nitrogen-doped carbon nanofibers (FeSe2@NCF) have been synthesized using the electrospinning and selenization process, which can alleviate the volume expansion and particle aggregation during the sodiation/desodiation and improve the electrical conductivity of the electrode. The FeSe2@NCF electrode delivers the outstanding specific capacity of 222.3 mAh g−1 at a fast current density of 50 A g−1 and 262.1 mAh g−1 at 10 A g−1 with the 87.8% capacity retention after 5000 cycles. Furthermore, the Na-ion full cells assembled with pre-sodiated FeSe2@NCF as anode and Na3V2(PO4)3/C as cathode exhibit the reversible specific capacity of 117.6 mAh g−1 at 5 A g−1 with the 84.3% capacity retention after 1000 cycles. This work provides a promising way for the conversion-based metal selenides for the applications as fast-charging sodium-ion battery anode.

Organic Composite Materials with Enhanced Cycling Stability and High-Rate Performance as Anodes for Aqueous Mg–Li Hybrid-Ion Batteries

Organic Composite Materials with Enhanced Cycling Stability and High-Rate Performance as Anodes for Aqueous Mg–Li Hybrid-Ion Batteries