Zn Batteries Research Articles

Co‐Substitution Engineering Boosting the Kinetics and Stablity of VO2 for Zn Ion Batteries

AbstractVO2 is considered as one of the most likely cathode materials to be commercialized for large‐scale application in AZIBs and is at the forefront of aqueous batteries, but its lower electrical conductivity, slower Zn2+ mobility, as well as voltage degradation and structural collapse due to vanadium solubilization have limited its further development. Herein, a Co‐substitution engineering strategy is proposed, which is introducing heteroatom Co2+ doping substitution and oxygen vacancy substitution to stabilize structure and promote ionic/electronic conductivity, leading an enhanced Zn ion storage behavior. The Co‐substituted VO2 (Co0.03V0.97O2‐x, denote as Ov‐CoVO) is reported in this paper, Co‐substitution inhibits vanadium dissolution of VO2 in AZIBs, even in the acetionitrile system. DFT calculations show that Ov‐CoVO has a more stable structure as well as a faster electronic/ionic conductivity. Consequently, the Ov‐CoVO||ZnOTF||Zn battery (aqueous) can deliver a remarkable capacity of 475 mAh g−1 at 0.2 A g−1 with 99.1% capacity retention after 200 cycles, still maintains excellent cycling stability in Ov‐CoVO||ZnTFSI||Zn (acetionitrile electrolyte) at 0.1 A g−1. In addition, compared to VO2, the charge transfer resistance and Zn2+ iffusion coefficient of Ov‐CoVO are significantly enhanced. This work broadens the scope for research cathode materials for high performance ZIBs.

Improving Zn2+ migration via designing multiple zincophilic polymer electrolyte for advanced aqueous zinc ion batteries

Aqueous zinc ion batteries (AZIBs)-based on Zn metal anode face serious issues of hydrogen evolution, corrosion, and zinc dendrite growth, limiting their practical applications. Polymer-based electrolytes can effectively inhibit the above issue, but usually bring additional interfacial resistance, resulting in slow reaction kinetics. Herein, we report a poly(4-acryloylmorpholine) electrolyte with multiple zincophilic primitives for fast zinc ion transport at bulk and interface of Zn metal anode (zinc ion transfer number of 0.77) via a facile one-pot polymerization. The special electrolyte structure with multiple zincophilic primitives can adhere tightly to the Zn metal anode and induce uniform Zn deposition, resulting in low interface resistance and enhanced cycling life of batteries. Therefore, the symmetric Zn||Zn batteries assembled based on the designed and synthesized polymer electrolyte can be stably cycled for 1400 with low overpotential (∼220 mV) at 0.5 mA cm−2 with a capacity of 0.5 mAh cm−2, and the corresponding V2O5||Zn full batteries exhibit attractive reversibility, rate performance, and cycling stability. The electrolyte engineering in this work paves a new path for the construction of polymer-based electrolytes for safe and stable AZIBs.

Harnessing Ion‐Dipole Interactions for Water‐Lean Solvation Chemistry: Achieving High‐Stability Zn Anodes in Aqueous Zinc‐Ion Batteries

AbstractThe reversibility and stability of aqueous zinc‐ion batteries (AZIBs) are largely limited by water‐induced interfacial parasitic reactions. Here, dimethyl(3,3‐difluoro‐2‐oxoheptyl)phosphonate (DP) is introduced to tailor primary solvation sheath and inner‐Helmholtz configurations for robust zinc anode. Informed by theoretical guidance on solvation process, DP with high permanent dipole moments can effectively substitute the coordination of H2O with charge carriers through relatively strong ion‐dipolar interactions, resulting in a water‐lean environment of solvated Zn2+. Thus, interfacial side reactions can be suppressed through a shielding effect. Meanwhile, lone‐pair electrons of oxygen and fluorinated features of DP also reinforce the interfacial affinity of metallic zinc, associated with exclusion of neighboring water to facilitate reversible zinc planarized deposition. Thus, these merits endow the Zn anode with a high‐stability performance exceeds 3800 hours at 0.5 mA cm−2 and 0.5 mAh cm−2 for Zn||Zn batteries and a high average Coulombic efficiency of 99.8 % at 4 mA cm−2 and 1 mAh cm−2 for Zn||Cu batteries. Benefiting from the stable zinc anode, the Zn||NH4V4O10 cell maintains 80.3 % of initial discharge capacity after 3000 cycles at 5 A g−1 and exhibits a high retention rate of 99.4 % against to the initial capacity during the self‐discharge characterizations.

Universal Strike-Plating Strategy to Suppress Hydrogen Evolution for Improving Zinc Metal Reversibility.

The development of highly reversible zinc (Zn) metal anodes is pivotal for determining the feasibility of rechargeable aqueous Zn batteries. Our research quantitively evalulates how the hydrogen evolution reaction (HER) adversely affects Zn reversibility in batteries and emphasizes the importance of substrate design in modulating HER and its associated side reactions. When the cathodic reaction is dominated by HER, the Zn electrode exhibits low plating/stripping efficiency, characterized by extensive coverage of a passivation layer that encompasses the electrochemical inactive Zn. Therefore, we propose a strike-plating strategy that modifies the pristine substrate by initiating Zn plating at a high current density for a short time. This straightforward and effective approach has been proven to suppress hydrogen evolution and transform the electrodeposition mode into one dominated by Zn reduction. Notably, Zn metal exhibits exceptionally high average reversibility of 98.80% over 200 h on a stainless steel substrate, which was typically precluded in aqueous electrolytes because of their favorable HER capability. Additionally, our strike-plating strategy demonstrates an appliable pathway to achieve high Zn reversibility on Cu substrate, showing an average efficiency of 99.83% over 540 h at a high areal capacity of 10 mAh cm-2 and high-performance Zn full cells with low N/P ratios. This research provides a foundation for future investigations into the underlying mechanisms of HER and strategies to optimize Zn-based battery performance.

Self-assembled polysilane artificial solid electrolyte interphase layer towards highly reversible zinc electrochemistry

Commercial applications of aqueous Zn batteries primarily encounter challenges related to surface corrosion and dendrite formation. In this study, a hydrophobic polysilane layer functionalized with −CF3 groups (CF3-PSiOX) is tailored for Zn anode through a two-step process involving self-assembly and condensation. The CF3-PSiOX layer functions as a protective barrier, effectively isolating water and inhibiting corrosion. Moreover, the primary interactions between −CF3 and Zn2+ guides the diffusion and deposition processes of Zn2+ while optimizing the de-solvation process, ultimately resulting in dendrite inhibition. Hence, cells with CF3-PSiOX layer boasts a high Coulombic efficiency (∼99.8 % after 1500 cycles), a long lifespan (over 2400 h), and optimized capacity retention (73.3 % over 1000 cycles). The self-assembled polysilane layer with customizable groups offers a novel approach for tuning the interface properties of Zn anodes and establishes a general principle for interface adjustment applicable to alternative metallic electrodes.

Ion confinement effect enabled by carboxymethyl cellulose/tannic acid hybrid hydrogel electrolyte toward stable zinc anode

Zinc metal batteries have garnered considerable attention ascribing to its cost effectiveness, intrinsic safety, and eco-friendliness. Nevertheless, zinc metal batteries yet are confronted with service life issue arising from dendrite and side reactions. Here, a highly ionic confined and hydrogen bond-enhanced tannic acid-modified carboxymethyl cellulose-based hybrid hydrogel electrolyte is designed for regulating structure of Zn2+ solvent and inhibiting dendrites growth, and simultaneously remaining operational under severe condition like low temperature. The phenolic hydroxyl group in tannic acid and the carboxyl group in carboxymethyl cellulose can respectively engage in chelation and coordination with Zn2+ to regulate Zn2+ transportation channel for guiding uniform zinc plating/stripping. Simultaneously, the enhanced ion confinement effect changes the solvation structure of Zn2+ to reduce H2O activity, effectively alleviating corrosion and hydrogen evolution reaction induced by H2O. Based on the principles of thermodynamics and reaction kinetics combined with theoretical calculations and experimental findings, the mechanism underlying its pivotal role in attenuating hydrogen evolution and fostering zinc deposition is elucidated systematically. The carboxymethyl cellulose/tannic acid hydrogel electrolyte endows exceptional cycling longevity (2, 100 h at 0.5 mA cm−2/0.25 mAh cm−2) for Zn||Zn battery, as well as high Coulombic efficiency for Zn||Cu battery (averagely 98.31 % within 500 cycles at 1 mA cm−2/mAh cm−2. Moreover, the assembled Zn||Zn battery, Zn||NH4V4O10 battery and Zn||NH4V4O10 pouch battery utilizing carboxymethyl cellulose/tannic acid hydrogel electrolyte can even function normally under severe conditions like low temperature and bending. This study provides valuable reference to develop hydrogel electrolytes with the ability to withstand low temperature and stabilize zinc anode.

Hydrophobic Ion Barrier-Enabled Ultradurable Zn (002) Plane Orientation towards Long-Life Anode-Less Zn Batteries.

Gradual disability of Zn anode and high negative/positive electrode (N/P) ratio usually depreciate calendar life and energy density of aqueous Zn batteries (AZBs). Herein, within original Zn2+-free hydrated electrolytes, a steric hindrance/electric field shielding-driven "hydrophobic ion barrier" is engineered towards ultradurable (002) plane-exposed Zn stripping/plating to solve this issue. Guided by theoretical simulations, hydrophobic adiponitrile (ADN) is employed as a steric hindrance agent to ally with inert electric field shielding additive (Mn2+) for plane adsorption priority manipulation, thereby constructing the "hydrophobic ion barrier". This design robustly suppresses the (002) plane/dendrite growth, enabling ultradurable (002) plane-exposed dendrite-free Zn stripping/plating. Even being cycled in Zn‖Zn symmetric cell over 2150 h at 0.5 mA cm-2, the efficacy remains well-kept. Additionally, Zn‖Zn symmetric cells can be also stably cycled over 918 h at 1 mA cm-2, verifying uncompromised Zn stripping/plating kinetics. As-assembled anode-less Zn‖VOPO4 ⋅ 2H2O full cells with a low N/P ratio (2 : 1) show a high energy density of 75.2 Wh kg-1 full electrode after 842 cycles at 1 A g-1, far surpassing counterparts with thick Zn anode and low cathode loading mass, featuring excellent practicality. This study opens a new avenue by robust "hydrophobic ion barrier" design to develop long-life anode-less Zn batteries.

Hydrophobic Ion Barrier‐Enabled Ultradurable Zn (002) Plane Orientation towards Long‐Life Anode‐Less Zn Batteries

Gradual disability of Zn anode and high negative/positive electrode (N/P) ratio usually depreciate calendar life and energy density of aqueous Zn batteries (AZBs). Herein, within original Zn2+‐free hydrated electrolytes, a steric hindrance/electric field shielding‐driven “hydrophobic ion barrier” is engineered towards ultradurable (002) plane‐exposed Zn stripping/plating to solve this issue. Guided by theoretical simulations, hydrophobic adiponitrile (ADN) is employed as a steric hindrance agent to ally with inert electric field shielding additive (Mn2+) for plane adsorption priority manipulation, thereby constructing the “hydrophobic ion barrier”. This design robustly suppresses the (002) plane/dendrite growth, enabling ultradurable (002) plane‐exposed dendrite‐free Zn stripping/plating. Even being cycled in Zn‖Zn symmetric cell over 2150 h at 0.5 mA cm‐2, the efficacy remains well‐kept. Additionally, Zn‖Zn symmetric cells can be also stably cycled over 918 h at 1 mA cm‐2, verifying uncompromised Zn stripping/plating kinetics. As‐assembled anode‐less Zn‖VOPO4·2H2O full cells with a low N/P ratio (2:1) show a high energy density of 75.2 Wh kg‐1full electrode after 842 cycles at 1 A g‐1, far surpassing counterparts with thick Zn anode and low cathode loading mass, featuring excellent practicality. This study opens a new avenue by robust “hydrophobic ion barrier” design to develop long‐life anode‐less Zn batteries.

Revealing the Limitation Induced by Hydroxyl in Regulating Solvation Structure of Zn2+ and Overcoming Challenges with Hybrid Additives towards Highly StableZinc Anodes.

In the field of electrolyte design for aqueous zinc-ion batteries (AZIBs), additives containing hydroxyl have been demonstrated to effectively modulate the solvation structure of Zn2+. However, reported studies typically focus solely on the effectiveness of hydroxyl while neglecting the issues that emerge during solvation structure regulation. The strong electron-attracting capability of Zn2+ attracts electrons from the oxygen in hydroxyl, thereby weakening the strength of hydroxyl, the hydrogen evolution reaction (HER) is also pronounced. This work innovatively reveals the limitation of hydroxyl-containing additives and proposes a synergistic regulation strategy based on hybrid additives. Arginine with a high isoelectric point is introduced into the electrolyte system containing hydroxyl additives. The protonation effect and electrostatic attraction of arginine enable it to absorb protons at the anode released by the weakened hydroxyl, thereby compensating for the limitation of hydroxyl additives. Under the synergistic action of hybrid additives, the Zn|Zn battery achieved stable deposition/stripping for over 1200 hours under 10 mA cm-2 and 10 mAh cm-2. Moreover, the Zn|Cu battery cycled for over 570 hours with a high Coulombic efficiency of 99.82%. This study presents a pioneering perspective for the further application of AZIBs.

Organic Cations Texture Zinc Metal Anodes for Deep Cycling Aqueous Zinc Batteries.

Manipulating the crystallographic orientation of zinc (Zn) metal to expose more (002) planes is promising to stabilize Zn anodes in aqueous electrolytes. However, there remain challenges involving the non-epitaxial electrodeposition of highly (002) textured Zn metal and the maintenance of (002) texture under deep cycling conditions. Herein, a novel organic imidazolium cations-assisted non-epitaxial electrodeposition strategy to texture electrodeposited Zn metals is developed. Taking the 1-butyl-3-methylimidazolium cation (Bmim+) as a paradigm additive, the as-prepared Zn film ((002)-Zn) manifests a compact structure and a highly (002) texture without containing (100) signal. Mechanistic studies reveal that Bmim+ featuring oriented adsorption on the Zn-(002) plane can reduce the growth rate of (002) plane to render the final exposure of (002) texture, and homogenize Zn nucleation and suppress H2 evolution to enable the compact electrodeposition. In addition, the formulated Bmim+-containing ZnSO4 electrolyte effectively sustains the (002) texture even under deep cycling conditions. Consequently, the combination of (002) texture and Bmim+-containing electrolyte endows the (002)-Zn electrode with superior cycling stability over 350h under 20 mAh cm-2 with 72.6% depth-of-discharge, and assures the stable operation of full Zn batteries with both coin-type and pouch-type configurations, significantly outperforming the (002)-Zn and commercial Zn-based batteries in Bmim+-free electrolytes.

Switching Hydrophobic Interface with Ionic Valves for Reversible Zinc Batteries.

Developing hydrophobic interface has proven effective in addressing dendrite growth and side reactions during zinc (Zn) plating in aqueous Zn batteries. However, this solution inadvertently impedes the solvation of Zn2+ with H2O and subsequent ionic transport during Zn stripping, leading to insufficient reversibility. Herein, an adaptive hydrophobic interface that can be switched "on" and "off" by ionic valves to accommodate the varying demands for interfacial H2O during both the Zn plating and stripping processes, is proposed. This concept is validated using octyltrimethyl ammonium bromide (C8TAB) as the ionic valve, which can initiatively establish and remove a hydrophobic interface in response to distinct electric-field directions during Zn plating and stripping, respectively. Consequently, the Zn anode exhibits an extended cycling life of over 2500 h with a high Coulombic efficiency of ≈99.8%. The full cells also show impressive capacity retention of over 85% after 1000 cycles at 5 A g-1. These findings provide a new insight into interface design for aqueous metal batteries.

Tuning Vertical Electrodeposition for Dendrites-Free Zinc-Ion Batteries.

Manipulating the crystallographic orientation of zinc deposition is recognized as an effective approach to address zinc dendrites and side reactions for aqueous zinc-ion batteries (ZIBs). We introduce 2-methylimidazole (Mlz) additive in zinc sulfate (ZSO) electrolyte to achieve vertical electrodeposition with preferential orientation of the (100) and (110) crystal planes. Significantly, the zinc anode exhibited long lifespan with 1500 h endurance at 1 mA cm-2 and an excellent 400 h capability at a depth of discharge (DOD) of 34% in Zn||Zn battery configurations, while in Zn||MnO2 battery assemblies, a capacity retention of 68.8% over 800 cycles is attained. Theoretical calculation reveals that the strong interactions between Mlz and (002) plane impeding its growth, while Zn atoms exhibit lower migration energy barrier and superior mobility on (100) and (110) crystal planes guaranteed the heightened mobility of zinc atoms on the (100) and (110) crystal planes, thus ensuring their superior ZIB performance than that with only ZSO electrolyte, which offers a route for designing next-generation high energy density ZIB devices.

Enhancing Secondary Alkaline Battery Performance: Synthesis and Electrochemical Characterization of Zn Anodes, Based on ZnO@C Core‐Shell Nanoparticles

AbstractWhile alkaline Zn batteries, like traditional rechargeable aqueous batteries, boast an advantage in terms of energy density, their progress has been hampered by concerns related to the anode. These concerns include issues like Zn dendrites, self‐corrosion, passivation, shape change, and the hydrogen evolution reaction (HER). To tackle these challenges, we have introduced a nanostructuring approach for the anode, employing carbon‐coated ZnO nanoparticles (ZnO@C) as the active material. In this study, we synthesized ZnO@C nanoparticles in an environmentally sustainable and scalable manner to address passivation and dissolution issues jointly. Nanoscale ZnO particles effectively prevent passivation, while carbon shell slows down the dissolution of zincate. The Zn anode exhibits a significant performance boost when compared to Zn foil and bare ZnO nanoparticles, even when subjected to demanding conditions (without the use of ZnO‐saturated electrolyte). This rechargeable Zn anode marks a significant step toward the realization of practical, high‐energy rechargeable aqueous batteries, such as Zn‐air batteries.

Non-sacrificial additive regulated electrode–electrolyte interface enables long-life, deeply rechargeable aqueous Zn anodes

Rechargeable aqueous Zn batteries (RAZBs) offer a promising solution for safe and cost-effective energy storage. However, practical applications of this type of battery are hindered by dendrite formation and side reactions, which primarily stem from the unstable Zn electrode–electrolyte interface (EEI). Here, we report 3-(1-pyridinio)-1-propanesulfonate (PPS) as a novel EEI regulator to tackle these critical issues. Theoretical calculations and experimental results reveal that PPS molecules can be preferentially adsorbed on the Zn anode surface and construct a lean-water EEI, which regulates uniform Zn plating/stripping and minimizes interfacial side reactions. As a result, the addition of PPS enables a Zn//Cu asymmetric cell to achieve an ultra-high Coulombic efficiency of 99.88 % and a lifespan of over 4,000 cycles (around half a year), far exceeding that with a conventional electrolyte (99.65 % and 210 cycles). Remarkably, even at 20 mA cm−2 and a high depth of discharge of 70 %, the Zn//Zn battery using the new electrolyte can still maintain an impressive cycling life of over 250 h. More importantly, the implementation of the designed electrolyte in various Zn-based full cells yields exceptional capacity retention and lifespan. This work underscores the importance of EEI regulation in advancing RAZB technology and offers a simple yet effective strategy for enhancing the stability and reversibility of Zn anodes, which represents a key step toward realizing the full potential of RAZBs for next-generation energy storage.

Solvation Barrier Remodeling‐Dictated Fast‐Kinetics Top–Down Zn Stripping/Plating in Water‐Lean Organic Electrolytes

AbstractDifferent from “bottom–up” Zn plating/stripping, “top–down” Zn stripping/plating provides a new perspective to reinvent current aqueous Zn batteries (AZBs), yet related studies remain absent. Herein, a chelation‐induced solvation barrier remodeling strategy is initiated toward fast‐kinetics “top–down” Zn stripping/plating in original Zn2+‐free water‐lean organic electrolytes (WLOE) for durable Zn batteries. It is found that in WLOE, the initial Zn stripping kinetics of the Zn anode remarkably limits the “top–down” Zn stripping/plating. The intervention of multidentate chelant (2‐methoxyethylamine, MEA) in WLOE greatly lowers the solvation reorganization energy of in situ stripped Zn2+ from the Zn anode, enabling the fast‐kinetics “top–down” Zn stripping/plating. Spectral characterization and fitted overpotential‐reorganization energy correlation strongly confirm the underlying mechanism. As such, the Zn stripping/plating in the MEA‐mediated WLOE shows a 90‐fold‐enhanced current response, triple‐lowered overpotential, and 170‐fold‐prolonged cyclability (over 1700 h at 0.5 mA cm−2) of those in MEA‐free counterpart. The assembled Zn||LiFePO4 hybrid full cell in MEA‐regulated WLOE exhibits a distinct and high voltage plateau of 1.50 V and a low polarization voltage of 0.14 V, far surpassing those in conventional WLOE. This work opens a new avenue to break the kinetics bottleneck of Zn stripping/plating in WLOE for durable Zn batteries.

Revealing Hydrogen Bond Effect in Rechargeable Aqueous Zinc-Organic Batteries.

The surrounding hydrogen bond (H-bond) interaction around the active sites plays indispensable functions in enabling the organic electrode materials (OEMs) to fulfill their roles as ion reservoirs in aqueous zinc-organic batteries (ZOBs). Despite important, there are still no works could fully shed its real effects light on. Herein, quinone-based small molecules with a H-bond evolution model has been rationally selected to disclose the regulation and equilibration of H-bond interaction between OEMs, and OEM and the electrolyte. It has been found that only a suitable H-bond interaction could make the OEMs fully liberate their potential performance. Accordingly, the 2,5-diaminocyclohexa-2,5-diene-1,4-dione (DABQ) with elaborately designed H-bond structure exhibits a capacity of 193.3 mAh g-1 at a record-high mass loading of 66.2 mg cm-2 and 100 % capacity retention after 1500 cycles at 5 A g-1. In addition, the DABQ//Zn battery also possesses air-rechargeable ability by utilizing the chemistry redox of proton. Our results put forward a specific pathway to precise utilization of H-bond to liberate the performance of OEMs.

Electrolyte‐Tailored Heterostructured Zinc Metal Anodes with Tunable Electric Double Layer for Fast‐Cycling Aqueous Zinc Batteries

AbstractThe structures and properties of the electric double layer (EDL) on zinc (Zn) anodes significantly influence the cycling and rate performance of aqueous Zn batteries (ZBs). Here, a strategy is reported to regulate the EDL structure through work function (Wf) engineering to effectively enhance the electrochemical performance of ZBs, which is enabled by electrolyte‐tailored growth of heterogenous metal with a large Wf on the Zn anode. The metal‐to‐metal charge transfer in heterostructured Zn metal induced by the disparity of Wf increases the surface charge density, which enriches the Zn ions and shortens the thickness of EDL. The compressed EDL weakens the repulsive force of Zn deposits to achieve a tightly stacked and dendrite‐free Zn deposition. Besides, the formed H2O‐deficient EDL structure enables the inorganic‐rich solid electrolyte interphase (SEI) with high Zn‐ion conductivity to inhibit the notorious parasitic reactions and improve the electrode reaction kinetics. Consequently, the Zn||Zn symmetric cells demonstrate an ultra‐long cycling life over 2700 cycles (the cumulative capacity reaches 5400 mA h cm−2) at a high current density of 50 mA cm−2. The Zn anodes show a high average Coulombic efficiency of 99.70% over 3650 cycles. The Zn||MnO2 full cells exhibit excellent practical‐level performance under cyclic continuous mode (3000‐cycle life at high rates) and cyclic intermittent mode (1170‐cycle life with 83.05% capacity retention). Practical pouch cells are also demonstrated with outstanding cycling performance.

A Wearable Self-Charging Electroceutical Device for Bacteria-Infected Wound Healing.

The prolonged wound-healing process caused by pathogen infection remains a major public health challenge. The developed electrical antibiotic administration typically requires metal electrodes wired to a continuous power supply, restricting their use beyond clinical environments. To obviate the necessity for antibiotics and an external power source, we have developed a wearable synergistic electroceutical device composed of an air self-charging Zn battery. This battery integrates sustained tissue regeneration and antibacterial modalities while maintaining more than half of the initial capacity after ten cycles of chemical charging. In vitro bacterial/cell coculture with the self-charging battery demonstrates inhibited bacterial activity and enhanced cell function by simulating the endogenous electric field and dynamically engineering the microenvironment with released chemicals. This electroceutical device provides accelerated healing of a bacteria-infected wound by stimulating angiogenesis and modulating inflammation, while effectively inhibiting bacterial growth at the wound site. Considering the simple structure and easy operation for long-term treatment, this self-charging electroceutical device offers great potential for personalized wound care.

Constructing surface protective film of V-Se-O to promote zinc ion storage by surface oxygen implantation strategy

Interfacial chemical modification is an effective strategy to adjust the strong Coulombic ion-lattice interactions with high valence cations experienced by electrode materials, facilitating the reaction kinetic. In this paper, a simple and fast surface oxygen implantation strategy was designed to adjust the electronic structure of stainless steel (SS) supported vanadium diselenide (VSe2) nanosheets and form a surface protective film, which effectively accelerates the reaction kinetics of Zn2+ and extends the cycle life of the battery. It is demonstrated that the conductivity, pseudocapacitance and specific capacity can be tuned by selectively introducing oxygen species to the surface, which provides an important reference for the design of electrodes with controlled surface chemistry. Density functional theory (DFT) calculations also confirm that the electronic structure can be adjusted by surface oxygen injection strategy, which not only improves the conductivity, but also adjusts the adsorption energy, thus providing favorable conditions for zinc ion storage. Benefiting from the selenium vacancies and pores generated by the removal of part of selenium, and the oxide film formed on the surfaces, the VSe2-xOx-SS-30 electrode showed higher specific capacity (188.4 mAh/g at 0.5 A g−1 after 50 cycles), better rate performance (107.1 mAh/g at 4 A g−1) and more satisfactory cycling stability (83.1 mAh/g at 5 A g−1 after 1800 cycles) than VSe2-SS electrode. Importantly, the flexible quasi-solid-state VSe2-xOx-SS-30//Zn battery also exhibits high specific capacity and excellent environmental adaptability. Furthermore, the zinc (de)intercalation and transformation reactions mechanism was revealed by some ex-situ/in-situ techniques.

Laser-Scribed Battery Electrodes for Ultrafast Zinc-Ion Energy Storage.

Aqueous Zn batteries are promising for large-scale energy storage but are plagued by the lack of high-performance cathode materials that enable high specific capacity, ultrafast charging, and outstanding cycling stability. Here, a laser-scribed nano-vanadium oxide (LNVO) cathode is designed that can simultaneously achieve these properties. The material stores charge through Faradaic redox reactions on/near the surface at fast rates owing to the small grain size of vanadium oxide and interpenetrating 3D graphene network, displaying a surface-controlled capacity contribution (90%-98%). Multiple characterization techniques unambiguously reveal that zinc and hydronium ions co-insert with minimal lattice change upon cycling. It is demonstrated that a high specific capacity of 553 mAh g-1 is achieved at 0.1 A g-1, and an impressive 264 mAh g-1 capacity is retained at 100 A g-1 within 10 s, showing excellent rate capability. The LNVO/Zn can also reach >90% capacity retention after 3000 cycles at a high rate of 30 A g-1, as well as achieving both high energy (369 Wh kg-1) and power densities (56306 W kg-1). Moreover, the LNVO cathode retains its excellent cycling performance when integrated into quasi-solid-state pouch cells, further demonstrating mechanical stability and its potential for practical application in wearable and grid-scale applications.