Specific Discharge Capacity Research Articles

Na Ions Doped Fe2VO4 Cathode for High Performance Aqueous Zinc-ion Batteries.

Aqueous zinc ion batteries are thought to be a new generation of secondary batteries that will replace lithium-ion batteries due to their great safety and inexpensive cost. In the cathode materials of aqueous zinc ion batteries with long life and high capacity, abundant active sites and crystal structure stability play an important role. In the present work, the strategy of Na+ intercalation of Fe2VO4 (FVO) is proposed, aiming at the insertion of Na+, which not only enriches the active sites, but also sodium and iron ions act as guest species with the negatively charged VOx lattice to provide strong electrostatic attraction to stabilize the lamellar structure. In terms of electrochemical performance, the discharge specific capacity is 370 mAh g-1 at a current density of 0.1 A g-1, and when the current density is arising 5 A g-1, the specific capacity also reaches 200 mAh g-1 after cycling 2000 with a capacity retention of 99 %, which is better than the electrochemical performance of Fe2VO4 (FVO) alone at 50 mAh g-1. The superior electrochemical performance proves that FVO-Na is an ideal cathode material for zinc ion batteries.

Interface engineering enabling thin lithium metal electrodes down to 0.78 μm for garnet-type solid-state batteries.

Controllable engineering of thin lithium (Li) metal is essential for increasing the energy density of solid-state batteries and clarifying the interfacial evolution mechanisms of a lithium metal negative electrode. However, fabricating a thin lithium electrode faces significant challenges due to the fragility and high viscosity of Li metal. Herein, through facile treatment of Ta-doped Li7La3Zr2O12 (LLZTO) with trifluoromethanesulfonic acid, its surface Li2CO3 species is converted into a lithiophilic layer with LiCF3SO3 and LiF components. It enables the thickness control of Li metal negative electrodes, ranging from 0.78 μm to 30 μm. Quasi-solid-state lithium-metal battery with an optimized 7.54 μm-thick lithium metal negative electrode, a commercial LiNi0.83Co0.11Mn0.06O2 positive electrode, and a negative/positive electrode capacity ratio of 1.1 shows a 500 cycles lifespan with a final discharge specific capacity of 99 mAh g-1 at 2.35 mA cm-2 and 25 °C. Through multi-scale characterizations of the thin lithium negative electrode, we clarify the multi-dimensional compositional evolution and failure mechanisms of lithium-deficient and -rich regions (0.78 μm and 7.54 μm), on its surface, inside it, or at the Li/LLZTO interface.

The Investigation of Fe─F Bond Chemistry on Structural Stability for Highly Durable Layered Na2FePO4F Cathode

AbstractLayered iron (Fe) ‐based fluorophosphates, Na2FePO4F (NFPF) stands for a cost‐effective and voltage‐advantageous cathode material for sodium‐ion batteries. Nevertheless, the lack of stability imposes constraints on its development and the decay mechanism remains shrouded in ambiguity. Herein, this work proposes the breakup of Fe─F bond in octahedral dimer accountable for the dissolution of redox centers and the formation of electrochemically inert phase, ultimately leading to the deterioration of electrochemical stability. To verify and address this, Boron (B) atoms situated in interstitial positions of PO4 tetrahedra appearing trigonal BO3 can be specifically targeted to enhance bond covalency and tailor electronic rearrangements at Fe─F bonds, thus stabilizing the octahedral dimer structure. This also facilitates rapid Na+ diffusion dynamics and accelerated electronic conductivity. As expected, NFPF‐B exhibits an ultra‐high discharge specific capacity (118.34 mAh g−1 at 0.1C) and excellent long‐term durability (capacity retention of 91.9% after 1000 cycles). The stability of the octahedra dimer is underscored by minimal volume change (2.9%) within the two‐stage biphase reaction of sodium storage mechanism. This work elucidates the enduring degradation mechanism of NFPF from octahedral dimers and offer theoretical guidance for Fe‐based cathode materials with prolonged stability.

A Method of Efficiently Regenerating Waste LiFePO4 Cathode Material after Air Firing Treatment.

Waste LiFePO4 (LFP) batteries can be harmful to the environment and lead to waste of resources if not properly disposed of. In this study, an efficient and environmentally friendly method for solid-phase recycling waste LFP cathode material (W-LFP) is proposed. Most of the impurities in the W-LFP are removed by air firing. The regenerated LFP is then obtained by adding lithium carbonate and triethanolamine for repair during heat treatment. The addition of triethanolamine converts Fe3+ to Fe2+ and also allows the formation of an N-doped modified carbon layer on the surface of the LFP particles, which improves the electrochemical properties of the regenerated material. Physical characterization and electrochemical tests are used to investigate the attenuation and regeneration mechanism of LFP. The regenerated LFP possesses a high specific discharge capacity (152.87 mAh g-1 at 0.2 C), which is about 95.32% of the commercial LFP, and the capacity retention rate is 88.52% after 600 cycles at 1 C. It is worth noting that we do not use solvents such as acids and alkalis in the regeneration process, thus avoiding the generation of large quantities of acid and alkaline waste liquids, which is friendly to the environment. This solid-phase regeneration process offers a promising method for the future recycling of used LFP batteries because of its simplicity, environmental friendliness, and high efficiency.

Multiple Strategies to Build High-Performance Spherical Na-Ion Layered Oxide Cathodes.

The development prospect of layered transition metal oxides in sodium-ion batteries is excellent, but there are some problems, such as poor cycle stability and a complex phase transition. The spherical NaNi0.25Fe0.15Mn0.3Ti0.1Sn0.05Co0.05Li0.1O2 (SP-HEO) has been developed to address the challenges faced by O3-type layered oxide in sodium-ion batteries. The SP-HEO material is synthesized by piling and high entropy. The multiple strategies combine to enhance the electrochemical performance and air stability. The SP-HEO demonstrated a specific discharge capacity of 150.1 mA h g-1 at 0.1 C and 100.4 mA h g-1 at 7 C. Ex situ XRD analysis confirmed that the SP-HEO effectively retards complex phase transitions. This study not only introduces a high-entropy design for high tap density spherical storage materials but also dispels industry concerns regarding the performance of sodium ion layered oxide cathode materials.

Waxberry-like TiO2 with Synergistic Surface Modification of Pyrolytic Carbon Coating and Carbon Nanotubes as an Anode for Li-Ion Battery.

Titanium dioxide (TiO2) as an anode material for lithium-ion batteries (LIBs) has the advantages of tiny volume expansion, high operating voltage, and outstanding safety performance. However, due to the low conductivity of TiO2 and the slow diffusion rate of lithium ions (Li+), it is limited in the application of LIBs. Therefore, waxberry-like TiO2 comodified by pyrolytic carbon coating and carbon nanotubes was prepared in this work. The waxberry-like TiO2 with nanorods on its surface shortens the diffusion distance of Li+. Carbon nanotubes and waxberry-like TiO2 are tightly combined through electrostatic assembly and form a cross-linked conductive network to provide more electron transmission paths. A thin layer of pyrolytic carbon wraps carbon nanotubes and waxberry-like TiO2, which enhance the conductivity of the composites and ensure the structural integrity of the materials throughout the cycling process. The experimental data revealed that the discharge-specific capacity of TiO2@CNT@C is 170.5 mAh g-1 after 3000 cycles at a large current density of 5 A g-1, and the discharge-specific capacity is still 143 mAh g-1 at the superhigh rate of 10 A g-1, which provides excellent rate performance and cyclic stability. The efficient dual-carbon modification strategy could potentially be extended to other materials.

"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 mAhg-1 at -35°C and 1 Ag-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.

Hierarchical van der Waals heterostructure with dual-defect sites for bidirectionally catalyzing Li2S nucleation and decomposition in lithium-sulfur batteries

The lithium‑sulfur batteries hold a promising option for the next generation of energy storage systems. Nevertheless, the shuttle effect of soluble lithium polysulfides and their slow reaction kinetics lead to extremely low efficiency and poor stability, thereby limiting the commercial viability of lithium‑sulfur batteries. Herein, MoSe2/Ti3C2 van der Waals heterostructure is synthesized with a dual-defect strategy, and its electrocatalytic performance is further improved through solution coating treatment (SCT), which involves the addition of glucose during the hydrothermal process. The conductive Ti3C2 scaffold effectively inhibits the aggregation of MoSe2 nanoflakes, thereby validating a larger active surface area. Meanwhile, the nitrogen dopant and selenium vacancy dual-defects in MoSe2 provide abundant active sites for anchoring polysulfides and catalyzing their conversion. As a result, the synergistic interaction between MoSe2 and Ti3C2 bidirectionally catalyzes the Li2S nucleation and decomposition through a heterointerface effect. The lithium‑sulfur battery equipped with MoSe2/Ti3C2-SCT heterostructure modified separator exhibits outstanding discharge specific capacity of 1496.9 mAh g−1 at 0.1C, and a low decay rate per cycle of 0.059 % after 500 cycles at 1C. The discharge specific capacity recovers to 89.3 % of the initial capacity when the current density is decreased from 5C to 0.1C. This work highlights the potential of defect engineering in transition metal selenides to enhance the performance of lithium‑sulfur batteries. It offers a new approach to designing composite electrocatalysts for high-performance lithium‑sulfur batteries.

Tailoring ORR Activity in Fe-N-C Catalysts through Phosphorus Incorporation.

Atomically dispersed iron and nitrogen co-doped carbon materials (Fe-N-C) represent promising non-precious metal catalysts for the oxygen reduction reaction (ORR), offering potential alternatives to noble metal-based benchmarks. In our study, we investigated the influence of phosphorus doping on the catalytic activity of Fe-N-C. The experimental research demonstrate that the doping of phosphorus significantly enhances the ORR activity. Specifically, the resulting Fe-NPC exhibits high metal loading and excellent ORR activity in 0.1 M KOH with an onset potential of 1.00 V and a half-wave potential of 0.864 V. Density functional theory (DFT) simulations reveal that phosphorus improves the electrocatalytic activity by activating O2 molecules and reducing the energy barrier (the hydrogenation reaction *OH→H2O) of the rate-determining step. Furthermore, Fe-NPC exhibits promising application prospects as an air cathode in Zn-air batteries, delivering a high maximum discharge power density of 180.3 mW cm-2 and outstanding discharge specific capacity (758.8 mAh g-1Zn) at a discharge current density of 10 mA cm-2.

Difluorobenzene as an Antisolvent for Fluorinated Electrolyte to Achieve Unparalleled Cycle Life of Lithium Metal Battery.

Electrolytes play a crucial role in enhancing the cycling stability and overall lifespan of lithium metal batteries (LMBs). However, conventional electrolytes achieve ununiform and low ionic conductivity solid electrolyte interphase (SEI), leading to uncontrolled lithium dendrite growth and dead lithium formation, rendering them inadequate for meeting the performance of high energy density LMBs. Herein, a 1,2-difluorobenzene (1,2-dFBn) is introduced as antisolvent in fluorinated electrolyte which is composed of fluoroethylene carbonate (FEC) and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI). The low energy level of the lowest unoccupied molecular orbital (LUMO) and the high fluorine-donating ability of 1,2-dFBn jointly modify the solvation structure and electrode/electrolyte interphase chemistry. As a result, this simple electrolyte formulation enables the Li||Li symmetric cells exhibit remarkable stability, enduring 700 h of continuous cycling under 2 mA cm-2 and Li||Cu cell achieve an impressive average Coulombic efficiency (CE) of 99.76%. Moreover, the full cell assembled with electrochemically deposited lithium capacity of 5 mAh cm-2 and LiFePO4 (LFP) as cathode achieves exceptional performance, maintaining a discharge specific capacity of 134.9 mAh g-1 while retaining 95.1% capacity at 2C after 1000 cycles. This study offers a plausible ratio design for fluorinated electrolyte, which achieving high CE and long-life LMBs.

Graphite Regeneration and NCM Cathode Type Synthesis from Retired LIBs by Closed-Loop Cycle Recycling Technology of Lithium-Ion Batteries

A closed-loop regeneration process for spent LiCoO2 has been successfully designed with prior synthesis of LiNixCoyMnzO2, by the authors. This research applies the methodology to lithium-ion battery anodes, using spent graphite from a decommissioned battery in a leaching process with 1.5 mol∙L−1 malic acid and 3% H2O2 alongside LiCoO2. The filtered graphite was separated, annealed in an argon atmosphere, and the filtrate was used to synthesize NCM cathode material. Characterization involved X-ray diffraction, EDX, and SEM techniques. The regenerated graphite (RG) showed a specific discharge capacity of 340.4 mAh/g at a 0.1C rate in the first cycle, dropping to 338.4 mAh/g after 55 cycles, with a Coulombic efficiency of 99.9%. CV and EIS methods provided further material assessment. In a related study, the SNCM111 synthesized from the leaching solution showed a specific discharge capacity of 131.68 mAh/g initially, decreasing to 115.71 mAh/g after 22 cycles.

Controllable Multilayer of High‐performance Si/C Anode Materials Synthesized at Low Temperature from Industrial Ca‐Si Alloy and CCl4 for Lithium‐ion Batteries

AbstractA simple and energy‐saving synthesis process for the high‐performance Si/C anode material of lithium‐ion batteries is advantageous for application. In this paper, the layered Si/C composite was synthesized by a low temperature one‐pot synthesis from industrial Ca−Si alloy and CCl4. The effect of synthesis temperature on the structure and performance of the products was investigated. We found that low temperature favors to the multilayer structure of Si/C. Taking the advantage of the layered structure, the Si/C‐300 anode material prepared at the temperature of 300 °C has good electrochemical performance of a reversible capacity of more than 1000 mAh g−1 at a current density of 2 A g−1 for 300 cycles, with a capacity retention ratio of 82.8 %, and an ICE of 77.0 %. At a high current density of 6 A g−1, the specific discharge capacity of 721.6 mAh g−1 can be achieved. The synthesis method provides a promising route to high performance silicon‐carbon anode materials.

N, F Co-Doped Carbon Material Self-Supporting Cathode for High-Performance Lithium-Oxygen Batteries.

The Li-O2 battery has emerged as a promising energy storage system due to its exceptionally high theoretical energy density of 3500 Wh kg-1. However, the sluggish kinetics associated with the formation and decomposition of discharge product Li2O2 poses several challenges in Li-O2 batteries, including excessive over-potential, limited rate performance, and reduced actual specific energy. Consequently, the development of cost-effective cathode catalysts with enhanced catalytic activity and long-term stability represents a viable approach to address these challenges. In this study, commercial melamine foam is utilized as a precursor material which was subjected to pyrolysis at elevated temperatures with PVDF to synthesize N, F co-doped self-supporting carbon cathode (NF-NSC). Remarkably, thanks to the synergistic effects of N, F heteroatomic in conjunction with the inherent three-dimensional reticular porous structure, NF-NSC exhibited enhanced electrochemical performance when utilized in Li-O2 batteries. Specifically, the NF-NSC cathode demonstrated an impressive discharge specific capacity of up to 35204 mAh g-1 alongside a low over-potential (0.86 V) and excellent cycling stability (146 cycles).

Ambient Synthesis of Vanadium-Based Prussian Blue Analogues Nanocubes for High-Performance and Durable Aqueous Zinc-Ion Batteries with Eutectic Electrolytes.

Prussian blue analogues (PBAs) have been widely studied in aqueous zinc-ion batteries (AZIBs) due to the characteristics of large specific surface area, open aperture, and straightforward synthesis. In this work, vanadium-based PBA nanocubes were firstly prepared using a mild in situ conversion strategy at room temperature without the protection of noble gas. Benefiting from the multiple-redox active sites of V3+/V4+, V4+/V5+, and Fe2+/Fe3+, the cathode exhibited an excellent discharge specific capacity of 200 mAh g-1 in AZIBs, which is much higher than those of other metal-based PBAs nanocubes. To further improve the long-term cycling stability of the V-PBA cathode, a high concentration water-in-salt electrolyte (4.5 M ZnSO4+3 M Zn(OTf)2), and a water-based eutectic electrolyte (5.55 M glucose+3 M Zn(OTf)2) were designed to successfully inhibit the dissolution of vanadium and improve the deposition of Zn2+ onto the zinc anode. More importantly, the assembled AZIBs maintained 55 % of their highest discharge specific capacity even after 10000 cycles at 10 A g-1 with superior rate capability. This study provides a new strategy for the preparation of pure PBA nanostructures and a new direction for enhancing the long-term cycling stability of PBA-based AZIBs at high current densities for industrialization prospects.

Improvement of electrochemical performance by surface modification of LiNi0.65Co0.15Mn0.2O2 cathode materials with SnO2

LiNi0.65Co0.15Mn0.2O2 batteries have attracted more and more attention due to their high energy density. However, LiNi0.65Co0.15Mn0.2O2 possesses adverse factors such as severe Li-Ni mixing and side reactions between active substance and electrolyte, which limits its electrochemical performance. Hence, we employed the SnO2 surface coating method to enhance its performance. SnO2 coating inhibits the direct contact between LiNi0.65Co0.15Mn0.2O2 and the electrolyte, which reduces the lithium-nickel mixing, enlarges the lithium layer spacing, and contributes to the improvement of the specific capacity of discharge and the cycling performance. The electrochemical results indicate the optimal SnO2-coated LiNi0.65Co0.15Mn0.2O2 show excellent cycling performance (85.0 % capacity retention for 100 cycles at 0.1 C) and multiplicative performance (124.1 mA·h·g−1 discharge specific capacity at 2 C). The paper highlights the SnO2 cladding technology which provides an excellent research idea to improve lithium-ion batteries.

Utilization of Y-MOF-derived Y2O3/YS@C heterojunction for Li-S battery separators

Due to its exceptional energy density and specific capacity, the lithium-sulfur battery is considered one of the most promising energy storage devices. However, the practical use of Li-S batteries is significantly hindered by both the shuttle effect and slow conversion of polysulfides. In order to address the shuttle effect of polysulfides, we utilized a Y-MOF derivative Y2O3/YS@C composite material as a modifier layer for Li-S battery separators. Initially, we synthesized Y-MOF by reacting tetra-hydroxyacetate yttrium and isophthalic acid in a solution. Subsequently, we sulfurized the Y-MOF precursor with thioacetamide and heat-treated it at high temperature to obtain Y2O3/YS@C composite material. The strong affinity of metal sulfides for sulfur provides chemical anchoring ability for polysulfide, while the heterogeneous structure can couple non-homogeneous regions together to produce synergistic effects and better catalyze polysulfides. By using Y2O3/YS@C as a separator modifier, we effectively suppressed the shuttle effect of polysulfides and improved electrochemical performance. At 3mgcm-2 sulfur loading, the initial discharge specific capacity of the Y2O3/YS@C separator at 0.5C was 966.1 mAh g-1; after 400 cycles, it still maintained a discharge specific capacity of 530.5 mAh g-1 with a capacity retention rate of 54.9%. When increasing sulfur loading to 5mgcm-2, the first-cycle discharge specific capacity at 0.l C was 831.4 mAh g-1; after 100 cycles, it was still 738.7 mAh g-1, with a capacity retention rate of 88.8%.

Breaking boundaries in O3-type NaNi1/3Fe1/3Mn1/3O2 cathode materials for sodium-ion batteries: An industrially scalable reheating strategy for superior electrochemical performance

To address the challenges of air stability and slurry processability in layered transition metal oxide O3-type NaNi1/3Fe1/3Mn1/3O2 (NFM) for sodium-ion batteries (SIBs), we have designed an innovative 500 °C reheating strategy. This method improves the surface properties of NFM without the need for additional coating layers, making it more efficient and suitable for large-scale applications. Pristine NFM (NFM-P) was first synthesized through a high-temperature solid-state method and then modified using this reheating approach (NFM-HT). This strategy significantly enhances air stability and electrochemical performance, yielding an initial discharge specific capacity of 151.46 mAh/g at 0.1 C, with a remarkable capacity retention of 95.04% after 100 cycles at 0.5 C. Additionally, a 1.7 Ah NFM||HC (hard carbon) pouch cell demonstrates excellent long-term cycling stability (94.64% retention after 500 cycles at 1 C), superior rate capability (86.48% retention at 9 C), and strong low-temperature performance (77% retention at −25 °C, continuing power supply at −40 °C). Notably, even when overcharged to 8.29 V, the pouch cell remained safe without combustion or explosion. This reheating strategy, which eliminates the need for a coating layer, offers a simpler, more scalable solution for industrial production while maintaining outstanding electrochemical performance. These results pave the way for broader commercial adoption of NFM materials.

Design and synthesis of FeS2/graphite sandwich structure with enhanced lithium-storage performance for lithium-ion and solid-state lithium batteries

As a conversion-type cathode material, FeS2 emerges as a promising candidate for the next generation of energy storage solutions, attributed to its cost-effectiveness, environment-friendliness and high theoretical capacity. However, several challenges hinder its practical application, including sluggish kinetics, insulating reaction products and significant volume fluctuation during cycling, which collectively compromise its rate capability and cycle stability. Herein, a well-designed sandwich structure of FeS2 embedded between graphite layers (FeS2/C) is obtained using a chloride intercalation and sulfidation strategy. The layered graphite-FeS2-graphite configuration boosts the active sites and adsorption capacity of Li+, thereby guaranteeing a high reversible capacity. Furthermore, the graphitic carbon matrix serves a dual purpose: it enhances electronic conductivity and restrain the volume fluctuation of FeS2 during long cycling. This combination ensures robust electrochemical kinetics, structural integrity and long life. Consequently, the FeS2/C composites exhibit exceptional lithium storage performance, achieving capacities of 506.2 mAh g−1 at 0.5 A/g and 277.2 mAh g−1 at 5.0 A/g. Additionally, the FeS2/C composites show promising potential as cathodes for all solid-state lithium batteries, showcasing high specific capacities of 658.0 mAh g−1 at 0.1 A/g for the second cycle and maintaining a cycle performance of 288.5 mAh g−1 after 800 cycles at 0.5 A/g. These values surpass the second discharge specific capacity of 96.1 mAh g−1 and cycle capacity of 25.3 mAh g−1 observed for Fe2O3/C composites. The discharge mechanism of FeS2/C composites was further characterized through in-situ transmission electron microscope test. This work provides valuable insights for designing and synthesizing FeS2, highlighting its potential for lithium ion storage and all solid-state lithium batteries.

Spontaneous built-in electric field in W-W2C@C heterostructure: Accelerating Sn2- directed migration in Li-S batteries

The commercialization of Li-S batteries is severely hindered by shuttle effect and sluggish redox reaction kinetics of LiPSs. Heterostructure can resolve the above shortcomings through the synergistic effect of adsorption and catalysis. However, long-chain LiPSs dissolving in electrolyte tend to cluster, resulting in low sulfur utilization and preventing kinetic conversion Thus, it is necessary to regulate the diffusion of Sn2− to achieve the directional diffusion from adsorbent to catalyst. Nevertheless, the design principle has not yet been clarified. W-W2C@C heterostructure with W of strong adsorption ability and high work function and W2C of excellent catalytic activity and low work function is designed by theoretical screening. Due to work function difference, this heterostructure controls the direction of the interface built-in electric field (BIEF), realizing the directional migration process of Sn2− from adsorptive W to catalytic W2C, thereby achieving a continuous “trapping-directional migration-conversion” reaction mechanism. The batteries have an excellent Li+ diffusion rate, high initial discharge specific capacity (1400.6 mAh/g at 0.2C), excellent rate capability (853.2 mAh/g at 2C), high reversible capacity (977.9 mAh/g after 150 cycles at 0.2C) and an extremely low capacity decay rate of 0.09 % per cycle after 300 cycles at 1C.

Separator functionalization realizing stable zinc anode through microporous metal-organic framework with special functional group

Aqueous zinc ion batteries (AZIBs) have been regarded as one of the most promising energy storage systems because of their security, high specific capacity and abundant zinc resources, etc. Despite the promising prospects of AZIBs, their practical application is still plagued by dendrite and side reactions on zinc surface. In this paper, glass fiber separators were modified by in-situ loading metal-organic framework MIL-125 (M-125) and its -NH2-functionalized material (NM-125). The designed separator pore structure was successfully adjusted and endowed with -NH2 functional groups, which can ultimately dramatically enhance the electrochemical performance of AZIBs under practical operation conditions. The functionalized NM-125 with smaller pore size and particle size enables NM-125-GF to prevent the transport of macromolecular anions in the electrolyte, guiding and promoting zinc ions to undergo an orderly migration. In addition, -NH2 of NM-125 can adsorb Zn2+ and detach them from the solvated structure, inhibiting the generation of anode-side reactions and optimizing battery performance. Notably, Zn||MnO2 full cell assembled with -NH2 functionalized separator also shows a high initial discharge specific capacity (160.2 mAh g-1) with a high capacity retention of ∼99.8% even after 700 cycles. The rational design of the functionalized separator provides a useful guideline for optimizing high-performance AZIBs.