Zinc-ion Batteries Research Articles

Poly(3,4-ethylenedioxythiophene)-Coated Vanadium-Doped MnO2 Nanorods for High-Performance Flexible Aqueous Zinc-Ion Battery Cathode.

Manganese-based aqueous zinc-ion batteries (AZIBs) are considered promising cathode materials for large-scale energy storage applications due to their low cost and high safety. However, the primary constraints on achieving high specific capacity and cycling stability are the inherent low conductivity and suboptimal structural stability of the AZIB cathodes. Herein, we report a high-performance poly(3,4-ethylenedioxythiophene) (PEDOT)-coated vanadium-doped MnO2 nanorod (NR) electrode for AZIBs. First, vanadium-doped MnO2 (V-MnO2) NRs were synthesized by a simple hydrothermal synthesis method. The V-MnO2 NRs were further encapsulated with a nanolayer of PEDOT through an in situ polymerization process, which was subsequently treated with sulfuric acid to achieve a smooth surface. The V doping creates oxygen vacancies within the MnO2, allowing for the rapid embedding and diffusion of Zn2+. The PEDOT nanolayer greatly enhances the conductivity and structural stability of the V-MnO2. Benefiting from the unique features, an optimal composite NRs electrode exhibits a high specific capacity of 250 mAh g-1 at 0.4 A g-1, a high energy density (388 Wh kg-1 at 151 W kg-1), and excellent stability over 5000 cycles at 3 A g-1. In addition, the flexible pouch cell assembled with the electrode shows good stability under bending. Given the positive outcomes, the material holds great potential for use as a cathode in next-generation flexible energy storage systems.

Enhancing Zinc Anode Stability with Gallium Ion‐Induced Electrostatic Shielding and Oriented Plating

AbstractThe cost‐effectiveness and environmental benefits of aqueous zinc‐ion batteries (ZIBs) have attracted considerable attention. However, practical applications are hindered by side processes including dendritic growth and hydrogen evolution corrosion. Herein, gallium ions (Ga3+) have been chosen as a multifunctional electrolyte additive to improve the reversibility of zinc‐ion batteries (ZIBs). Remarkably, Ga3+ ions adhere to the anode surface, establishing a dynamic electrostatic shielding layer that modulates Zn2+ deposition and prevents side reactions. Typically, Ga3+ ions preferentially adsorb onto the (002) and (110) planes of Zn, facilitating preferential deposition on the (100) plane, resulting in a dendrites‐free zinc anode. Consequently, the Zn||Zn symmetrical cell with Ga3+‐modified electrolyte demonstrates a prolonged lifespan of 4000 h, while the Zn||Ti asymmetric cell exhibits an impressive coulombic efficiency of 99.12% for zinc stripping and plating at 2 mA cm−2. Additionally, the Zn||VO2 cell maintains high capacity retention after 1500 cycles at 5 A g−1. This work presents Ga3+ ions as an electrolyte additive, facilitating the development of a durable dynamic electrostatic shielding effect and preferential (100) plane electroplating, ensuring zinc deposition free from dendrite formation. Such discoveries form a basis for future investigations into novel materials to propel advancements in metal battery technology.

Cobalt-doped copper sulfide nanocomposite integrated with graphene oxide as a high-performance conversion anode for aqueous zinc-ion batteries

Rechargeable aqueous zinc-ion batteries (ZIBs) encounter substantial obstacles arising from the inherent dilemmas of dendrite growth, hydrogen gas evolution, and corrosion affiliated with zinc metal anodes, thereby highlighting the necessity for researching conversion anode materials as a promising pathway forward. Copper sulfide (CuS) has been demonstrated as a promising conversion anode material for ZIBs due to its notable electrochemical performance, while challenges persist regarding the Coulombic interactions between Zn2+ and host anions, coupled with the material’s fundamental conductivity that remains less than fully satisfactory. To address the above issues, we have designed and synthesized a nanostructured composite of cobalt doped CuS integrated in graphene oxide frames (GO/Co-CuS) as anode for ZIBs. The cobalt doping serves to alleviate Coulomb interaction (Coulomb attraction) between Zn2+ and host anions, thereby enhancing the kinetics of Zn2+ diffusion. Furthermore, the incorporation of GO framework improves the electrical conductivity of the material and mitigates volume expansion during the reaction process. The synergistic effect engendered by the combination of cobalt doping and the incorporation of a GO framework results in the remarkable electrochemical performance exhibited by GO/Co-CuS. The GO/Co-CuS composite nanostructure exhibited commendable rate capability and cycling stability. Specifically, it exhibits remarkable rate capability, delivering 296 mAh g−1 at 1 A/g and 168 mAh g−1 at 10 A/g. Furthermore, after 1000 cycles at a high current density of 10 A/g, it maintains a capacity of 166 mAh g−1, demonstrating exceptional cycling stability. Additionally, the full-cell configuration of GO/Co-CuS//MnO2@CNTs, when cycled 241 times at 2 A/g, retains a capacity of 79 mAh g−1, thereby confirming the practical efficacy of the GO/Co-CuS nanocomposite as an efficient conversion anode for ZIBs.

Engineering of charge density at the anode/electrolyte interface for long-life Zn anode in aqueous zinc ion battery.

The aqueous zinc ion battery emerges as the promising candidate applied in large-scale energy storage system. However, Zn anode suffers from the issues including Zn dendrite, Hydrogen evolution reaction and corrosion. These challenges are primarily derived from the instability of anode/electrolyte interface, which is associated with the interfacial charge density distribution. In this context, the recent advancements concentrating on the strategies and mechanism to regulate charge density at the Zn anode/electrolyte interface are summarized. Different characterization techniques for charge density distribution have been analysed, which can be applied to assess the interfacial zinc ion transport. Additionally, the charge density regulations at the Zn anode/electrolyte interface are discussed, elucidating their roles in modulating electrostatic interactions, electric field, structure of solvated zinc ion and electric double layer, respectively. Finally, the perspectives and challenges on the further research are provided to establish the stable anode/electrolyte interface by focusing on charge density modifications, which is expected to facilitate the development of aqueous zinc ion battery.

Novel synthesis of Zn2(V3O8)2 and its application to aqueous zinc-ion batteries

Aqueous zinc-ion batteries, with their high capacity and stable zinc anode, are a promising choice for large-scale energy storage systems. To fabricate promising cathode materials for aqueous zinc-ion batteries, the VO2(M)-C composite was designed and synthesized in this work by a simple hydrothermal reaction and high-temperature calcination. The VO2(M)-C composite undergoes an in situ electrochemical conversion during the initial cycle of activation when it is charged to 1.4–1.55 V, generating Zn2(V3O8)2 with large layer spacing and a stable structure. The activated cathode material exhibited high specific capacity (520.64 mA h g−1 at 0.5 A g−1) and excellent cycling stability (215.17 mA h g−1 after 1000 cycles at 20 A g−1). These excellent performances are mainly attributed to the high pseudo-capacitance contribution ratio as well as the good electronic conductivity and fast ionic diffusion. This study brings new prospects of designing high-performance cathode materials for aqueous zinc-ion battery.

Electrochemical constructing versatile ZnAl-LDH artificial interface layer coated (002)-textured Zn for highly reversible zinc anodes

Rechargeable aqueous zinc-ion batteries (AZIBs), renowned for their high safety, cost-effectiveness, and high energy density, are regarded as an alternative for large-scale energy storage. However, persistent challenges remain in achieving highly reversible AZIBs, primarily centered around the notorious issues associated with the Zn anode. Here, a zincophilic Zn-Al layered double hydroxide (ZnAl-LDH) artificial interface layer coated highly (002)-textured Zn metal anode (SZ/LDH@Zn) with an integrated design are successively constructed by electrochemical methods. Comprehensive characterizations and theoretical calculations reveal that the preferred (002)-textured Zn couping with the zincophilic ZnAl-LDH coating layer not only can effectively regulate the interfacial electric field and Zn2+ flux distribution, guiding a uniform and horizontal Zn2+ deposition but also provide inherent Zn2+ diffusion channels, accelerating its interfacial transport kinetics. Moreover, the ZnAl-LDH layer with good chemical stability acted as a robust physical barrier, impeding direct contact between the electrolyte and Zn anode, thus curbing interfacial side reactions. As a result, the SZ/LDH@Zn||SZ/LDH@Zn symmetric cell delivers unprecedented cycling stability of 5500 h (about 230 days) at 1 mA cm−2, 1 mA h cm−2. The SZ/LDH@Zn||Cu asymmetric cell achieves superior reversibility with a high average Coulombic efficiency of 99.85 % over 3800 cycles. More significantly, the SZ/LDH@Zn||NaV3O8·xH2O full cell with a low N/P ratio (3.62) exhibits an impressive areal capacity of 5.36 mA h cm−2 and reliable operation over 1500 cycles. This work offers a facile and controllable electrochemical coupling strategy to build a highly stable Zn metal anode.

Theoretical study of HfS2 as anode material of zinc ion battery in sports wearable equipment

In this study, the density functional theory (DFT) based on first-principles calculations was used to conduct a comprehensive theoretical calculation of the Zn adsorption HfS2 system (Zn-HfS2) to develop the potential of HfS2 as an anode material for zinc ion batteries (ZIBs). The calculation results show that the adsorption energy decreases gradually (−1.368 eV) with the increase of shear deformation. There is a significant charge transfer from Zn to HfS2 monolayer, and the electrons of Zn atoms flow to S atoms. The intrinsic HfS2 shows a band gap value of 2.055 eV, and Zn-HfS2 shows a metal property with a zero band gap. The adsorption of Zn leads to an increase in energy near the Fermi level, indicating that the adsorption of Zn enhances the electronic conductivity of HfS2. The deformation reduces the barrier of Zn in the diffusion path to 0.16 eV. The maximum specific capacity of HfS2 to Zn is 447.445 mAh/g. The calculation results will help promote the application of zinc ion batteries in wearable devices.

Targeting inerratic deposition behaviour via interface regulation toward dendrite-free zinc metal anodes

Aqueous zinc ion batteries are of interest due to their inherent safety, low cost and high energy density. Nevertheless, critical issues such as uncontrollable dendrite growth, hydrogen evolution reaction and corrosion have dramatically impeded the widespread utilization. To tackle above issues, the versatile artificial protective layer strategy consisting of Zn-friendly, porous and conductive carbon shells is presented for yolk-shell SiO2@void@C (SVC) nanospheres for guiding rapid and homogeneous Zn plating/stripping. On the one hand, the highly zincophilic SiO2 and pore structure interacted significantly with low nucleation overpotential and uniform Zn2+ flux, which favored homogeneous zinc deposition and ionic migration, thereby dramatically aiding in inhibition of Zn dendrites and interruption of interfacial side reactions. On the other hand, SVC nanospheres confer excellent electrical conductivity and mechanical properties, which play an important role in accelerating ion diffusion and boosting structural stability. Consequently, the SVC@Zn electrode exhibits high reversibility and electrochemical stability with a long cycling stability of 1800 h at 5 mA cm−2/1.25 mAh cm−2 and average CE of 99 %. The good properties associated with composition simplicity and abundant yield affords a feasible scheme for high-performance AZIBs.

Double Network Gel Electrolyte with High Ionic Conductivity and Mechanical Strength for Zinc-Ion Batteries.

Gel electrolytes hold promise for stabilizing zinc-ion batteries (ZIBs), but achieving both high ionic conductivity and strong mechanical properties remains challenging. This work presents a double network gel electrolyte based on poly(N-hydroxymethyl acrylamide) (PNMA) and sodium alginate (SA), overcoming this trade-off. The PNMA network provides mechanical strength and water retention, while the SA network facilitates rapid zinc-ion (Zn2+) diffusion through tailored solvation. This double network gel exhibits a tensile strength of up to 838 kPa, significantly higher than previous reports. The SA network provides ion channels for rapid transport of hydrated Zn2+, enhancing the ionic conductivity to a ground-breaking 33.1 mS cm-1. This value is even higher than the liquid electrolytes. The growth of Zn dendrites is also suppressed due to the mechanical constraint and rapid ion conduction. In symmetrical cells, the PNMA/SA gel demonstrates exceptional cycling stability (>2000 h). Characterizations show this is because of reduced free water amount, hindering cathode material dissolution. The full cells with sodium vanadate cathode manifest a high capacity (364.8 mA h g-1 at 0.5 A g-1) and excellent capacity retention (83% after 2500 cycles at 10 A g-1). This double network design offers a way to achieve high-performance and stable ZIBs.

Mn-deficient ZnMn2O4/Zn0.5Mn0.5Fe2O4 cathode for enhancing structural reversibility and stability of zinc-ion batteries

Aqueous zinc-ion batteries have surfaced as a viable energy storage technology due to their safety, eco-friendliness, and cost-effectiveness. Binary zinc manganite oxide (ZnMn2O4 or ZMO) stands out as the potential cathode material owing to its considerable theoretical capacity and high operating voltage. However, high electrostatic repulsion of Zn2+ ions within ZMO leads to sluggish diffusion and poor reversibility of Zn2+ ions insertion/extraction that can reduce charge storage and overall cycling performance. This study addresses this challenge by introducing FeCl3 during the synthesis to form ZMO/Zn0.5Mn0.5Fe2O4 (ZMFO) cathode material. This cathode features Mn-deficient structures, which can reduce the electrostatic repulsion via low Mn occupancies and lattice parameters enlargement, thus facilitating Zn2+ ions diffusion. Ex-situ X-ray diffraction analyses further show that the cathode is able to maintain good structural reversibility during the charge-discharge cycles. Additionally, the ZMO/ZMFO cathode exhibits smaller particle sizes than pristine ZMO, providing a wider surface area. The presence of ZMFO with a large unit cell volume can also enhance Zn storage capacity and accelerate Zn2+ ions kinetics. Highlighting those advantages, aqueous zinc-ion batteries with ZMO/ZMFO cathode show a capacity of ~230 mAh g−1 at 0.05 A g−1 and retain 99 % of its initial capacity at 0.2 A g−1 after 200 cycles of charge-discharge.

Oxygen-deficient NH4V4O10 cathode with Ag quantum dots and interlayer Ag+ towards high-performance aqueous zinc ion batteries

Herein, oxygen-deficient NH4V4O10 micro-flowers with loaded Ag quantum dots and pre-intercalated Ag+ (NVO-Ag) for aqueous zinc ion battery (AZIB) cathode materials were successfully synthesized by a one-step hydrothermal method. The reversible redox reaction between Ag+ and Ag quantum dots, and the abundant Zn2+ storage sites from oxygen vacancies provided capacity contributions for NVO-Ag. Meanwhile, the loaded Ag quantum dots, pre-intercalated Ag+ and introduced oxygen vacancies synergistically optimized the electronic structure and distribution of NVO-Ag, promoting the transport of electrons in NVO-Ag. The pre-intercalated Ag+ could also replace the NH4+ in the interlayer of NH4V4O10, weakening the repulsion between the interlayer NH4+ and Zn2+, which achieved rapid Zn2+ diffusion kinetics. Moreover, the abundant oxygen vacancies in NVO-Ag could alleviate the strong electrostatic interaction between Zn2+ and V-O framework, boosting the transmission of Zn2+ in NVO-Ag. Finally, the structural stability of NH4V4O10 micro-flowers was improved due to the high bonding strength between Ag+ and V-O layers. Benefiting from the above effects, NVO-Ag-100 achieved excellent capacity performance (387.2 mAh g−1 at 0.5 A g−1), rate performance (178.9 mAh g−1 at 12 A g−1) and cycle stability (91.7 % capacity retention after 1700 cycles at 8 A g−1). This work provided effective ideas to achieve high-performance AZIB cathode materials.

One-step oil bath preparation of cobalt-doped MnO2/coconut activated carbon composite with superior zinc ion storage performance

MnO2 is a prospective cathode material for aqueous zinc ion batteries due to its high theoretical capacity and low cost. However, bare MnO2 usually suffers from large volume change and dissolution problems. In this work, Co-doped MnO2/coconut activated carbon composite (Co-β-MO/CAC) has been successfully synthesized by a one-step oil bath method. The electrochemical impedance spectroscopy (EIS) and galvanostatic intermittent titration technique (GITT) tests demonstrate that both the Co doping and the incorporation of coconut activated carbon can effectively reduce the electrochemical reaction resistance of MnO2 and improve the intercalation and deintercalation abilities of H+ and Zn2+. The combined effect of the Co doping and CAC compositing has resulted in excellent electrochemical property of Co-β-MO/CAC. After 120 cycles at 0.2 A g−1, the capacity of Co-β-MO/CAC increases from 224.7 mAh g−1 to 436.7 mAh g−1. Moreover, the composite can also deliver a high reversible capacity of 233.2 mAh g−1 after 900 cycles at 0.5 A g−1.

An organic cathode integrating carbonyl and imino groups for high-performance aqueous zinc-ion battery with air self-charging ability

Air-self-charging aqueous zinc-ion batteries (AZIBs) are a promising system applied in some special occasions, where no external power source can be provided to recharge the battery. Here, a new π-conjugated aromatic compound 2,7,12-tri(4H-1,2,4-triazol-4-yl)-1H-pyrrolo [3,4-b]pyrrolo[3′,4′:5,6]pyrazino[2,3f]pyrrolo[3′,4′:5,6]pyrazi-no[2,3−h]quinoxaline-1,3,6,8,11,13(2H,7H,12H)-hexaone (THQH) is reported. Because THQH contains multiple redox-active groups (CN and CO) and its insolubility in 2 M ZnSO4, as the cathode material of flexible/coin-type AZIBs, it owns outstanding discharge specific capacity, higher-rate performance and longer cycle life. Various ex-situ experiments and theoretical calculation revealed H+ and Zn2+ participated in the THQH cathode reaction. Notably, as the discharged flexible Zn//THQH battery is exposed to air, it can be self-recharged via the redox reaction between oxygen in air and the discharged THQH cathode, along with H+ ions removal. The flexible Zn//THQH battery can deliver a discharge capacity of up to 566 mA h g−1 at 0.5 A g−1, a higher-rate capability and an excellent self-charging cycle stability (31 cycles) after exposed to air for 28 h, displaying an excellent reusability. This work paves a way for the development of high-performance flexible air self-charging AZIBs.

Organic molecular intercalation regulated hydrated vanadate cathodes with improved electrochemical properties and fast kinetics for aqueous zinc-ion batteries

Due to the large hydrated zinc ion radius resulting from the stable solvation structure with six water molecules in electrolyte, the interlayer spacing of most vanadium-based materials fails to meet the requirements for efficient insertion and extraction of Zn2+. Therefore, it is crucial to optimize and reconstruct the VO layer structure in order to achieve rapid and stable zinc storage. In this paper, composites of phenylalanine methyl ester (PM) inserted hydrated V2O5 (PMVO) are prepared using a one-step hydrothermal method. With the increase of PM insertion, the electrochemical properties initially exhibit enhancement followed by subsequent decline. Notably, PMVO-1.6 presents exceptional electrochemical performance, including a high capacity of 464 mAh g−1 at 0.1 A g−1, excellent rate capability with 220 mAh g−1 at 7 A g−1, and superior cycling stability with 97.5 % capacity retention after 1000 cycles at 4 A g−1. The incorporation of PM not only serves as stable structural pillars, but also reduces the solubilization of vanadium, facilitates the diffusion kinetics of hydrated zinc ions, and enhances the surface pseudo-capacitance effect.

Overcoming Ion Trapping in Chevrel Phase Compounds via Tailored Anion Substitution: An Integrated Study of Theory, Synthesis, and In Operando Techniques for Reversible Aqueous Zn-Ion Batteries.

Sustainable batteries are key for powering electronic devices of the future, with aqueous zinc-ion batteries (AZIBs) standing out for their use of abundant, readily available elements, and safer production processes. Among the various electrode materials studied for AZIBs, the Chevrel Phase, Mo6S8 has shown promise due to its open framework, but issues with zinc ion trapping have limited its practical application. In this work, we employed computational methods to investigate the insertion-deinsertion mechanism in a series of isostructural Mo6S8-xSex (x = 0-8) solid solutions as materials that could balance the gravimetric capacity and reversible cycling for AZIBs. Density functional theory (DFT) calculations revealed that increasing the Se content would reduce the binding energy of Zn within the structures, enabling Zn deinsertion compared to the Mo6S8 structure. Experiments confirmed the formation of Mo6S8-xSex (x = 0-8) solid solutions, and electrochemical testing showed improved reversibility of Zn insertion/deinsertion as the amount of Se increased, consistent with the computational predictions. Furthermore, combined in operando X-ray diffraction and electrochemical studies revealed a continuous, gradual Zn-insertion process into Mo6S4Se4, in stark contrast to the abrupt phase changes observed upon Zn insertion in Mo6S8 and Mo6Se8. DFT calculations attributed the stabilization of Zn0.5Mo6S4Se4 as a prime reason for preventing phase separation, making Se-substituted compounds promising materials for high-performance AZIBs. Overall, this interdisciplinary approach, integrating computational modeling, materials synthesis, and advanced characterization techniques, offers a pathway for fine-tuning anion chemistry that can help create high-performance electrode materials for sustainable energy storage technologies.

Sustainable Fabrication of Graphene Oxide Cathodes from Graphite of Failed Commercial Li-Ion Batteries for High-Performance Aqueous Zn-Ion Batteries.

The need for revamping spent graphite (SG) from battery waste of commercial lithium-ion batteries and employing it as a source for the synthesis of graphene oxide (GO) is focused. Thus, this work emphasizes the study of GO sheets, synthesized via modified Hummer's method from spent graphite (SG-GO) as cathodes for an aqueous zinc ion battery (AZIB) system, for the first time in literature. For comparison, graphene oxide is also synthesized using commercial graphite powder, its structural and morphological properties are analyzed with SG-GO. The coin cell AZIB device is fabricated for both the GOs and the electrochemical performances revealed that SG-GO portrayed an enhanced charge capacity of 270 mAh g-1 at 0.1 A g-1 in 3m ZnSO4 in comparison to GO which delivered ≈198 mAh g-1 at the same current density of 0.1 A g-1. The long-run cycling analysis of SG-GO elucidated the capacity retention of 77.3% at 1 A g-1 even after 1000 cycles. Moreover, the performance of SG-GO is inspected in different electrolyte systems and the suitable electrolyte underwent concentration variation studies to figure out the capability of the system in storing Zn2+ ions which is found to be more in 3M ZnSO4 electrolyte.

Dendrite-free zinc metal anode for long-life zinc-ion batteries enabled by an artificial hydrophobic-zincophilic coating

Considering the desired energy density, safety and cost-effectiveness, rechargeable zinc-ion batteries (ZIBs) are regarded as one of the most promising energy storage units in next-generation energy systems. Nonetheless, the service life of the current ZIBs is significantly limited by rampant dendrite growth and severe parasitic reactions occurring on the anode side. To overcome these issues caused by poor interfacial ionic conduction and water erosion, we have developed a facile strategy to fabricate a uniform zinc borate layer at the zinc anode/electrolyte interface (ZnBO). Such protective layer integrates superhydrophobic-zincopholic properties, which can effectively eliminate the direct contact of water molecules on the anode, and homogenize the interfacial ionic transfer, thereby enhancing the cyclic stability of the zinc plating/stripping. As a result, the as-prepared ZnBO-coated anode exhibits extended lifespan of 1200 h at 1 mA cm−2 and demonstrates remarkable durability of 570 h at 20 mA cm−2 in Zn||Zn symmetric cells. Additionally, when coupled to an NH4V4O10 (NVO) cathode, it also delivers a superior cyclability (203.5 mAh/g after 2000 cycles at 5 A/g, 89.3 % capacity retention) in coin full cells and a feasible capacity of 2.5 mAh at 1 A/g after 200 cycles in pouch full cells. This work offers a unique perspective on integrating hydrophobicity and zincophilicity at the anode/electrolyte interface through an artificial layer, thereby enhancing the cycle lifespan of ZIBs.

Synergistic effect of oxygen defects and calabash-like hollow carbon matrix enables VO2 as high-performance cathode for zinc ion battery

Vanadium dioxide (VO2) materials exhibit significant theoretical specific capacity, which is ascribed to multi-electron transfer reactions and unique tunneled structures. However, the low electronic conductivity and sluggish reaction kinetics of VO2 have impeded its further development. Hence, in this study, we employed a synergistic strategy of defect engineering and compositing with a calabash carbon matrix to reduce Zn2+ diffusion barriers and accelerate electron transfer. The VO2 cathode provided a high specific capacity at a low rate of 303 mA h g−1 at 0.1 A g−1 after 191 cycles, along with good rate performance (168 mA h g−1 at 10 A g−1) and satisfactory long-term stability (170 mA h g−1 at 1 A g−1 after 1100 cycles). The exhaustive structural analyses indicated that oxygen vacancies accelerated the Zn2+ diffusion rate, while a uniform calabash-like hollow carbon matrix improved electronic conductivity during cycling. Moreover, ex-situ measurements demonstrated that during discharge, the composite cathode transformed to layered Zn3+x(OH)2V2O7·2H2O, which then facilitated the subsequent intercalation of Zn2+. This cooperative strategy advances the practical application of aqueous zinc ion batteries by leveraging vanadium-based electrodes.

Promoting Preferential Zn (002) Deposition with a Low-Concentration Electrolyte Additive for Highly Reversible Zn-Ion Batteries.

Aqueous zinc-ion batteries have promising potential as energy storage devices due to their low cost and environmental friendliness. However, their development has been hindered by zinc dendrite formation and parasitic side reactions. Herein, we introduce a low-concentration sodium benzoate (NaBZ) electrolyte additive to stabilize the electrode-electrolyte interface and promote deposition on the Zn (002) crystal plane. From experimental characterization and computational analyses, NaBZ was found to adsorb on the Zn surface and inhibit side reactions while guiding homogeneous Zn deposition on the (002) plane. Consequently, Zn|Zn symmetric cells with the NaBZ additive cycled stably for over 1000 h at a current density of 0.5 mA cm-2 and an areal capacity of 0.5 mAh cm-2, while Zn|Cu cells showed excellent reversibility with a Coulombic efficiency of 99.05%. Moreover, Zn|Na0.33V2O5 full cells achieve a high specific capacity of 124 mAh g-1 while cycling for 600 h at 2 A g-1. These findings present a low-cost electrolyte modification strategy for reversible zinc-ion batteries.

Regulating oxygen vacancies in ammonium vanadate electrode materials for advanced aqueous zinc ion batteries

In the past decade, vanadates have attracted one's attention as the electrode materials for aqueous zinc ion batteries (AZIBs). Nevertheless, their structural instability and sluggish ion/electron dynamics lead to an inevitable decline in the electrochemical performance. To address these issues, we introduce oxygen vacancies into NH4V4O10 nanosheets to improve the ion transport rate during the electrochemical reaction. The prepared NHVO-40 samples provide many active sites compared to NH4V4O10 materials. The assembled cell delivers a capacity of 452.03 mAh g-1 at a current density of 0.2 A g-1. It also presents a retention rate of 94.6% at 10 A g-1 after 4000 times cycling. In addition, they still possess an energy density of 332.5 Wh kg-1 at a power density of 70W kg-1.