Fast Zn2 Research Articles

Phase Engineering of ZnSe by Small Molecules as a High-Performance Protective Layer for Zn Anode.

The practical application of aqueous zinc ion batteries is still hampered by the side reactions and dendrite growth on Zn anode. Herein, the phase engineering of ZnSe coating layer by incorporating small molecules is developed to enhance the performance of Zn anode. The unique electronic structure of ZnSe⋅0.5N2H4 promises strong adsorption for Zn atoms and enhanced ability to inhibit hydrogen evolution, thereby promoting uniform Zn deposition and preventing by-product and dendrite growth. Meanwhile, fast Zn2+ transfer and deposition kinetics are also demonstrated by ZnSe⋅0.5N2H4. As a result, the ZnSe⋅0.5N2H4@Zn symmetric cell achieves long-term cycling stability up to 1900 h and 300 h at high current densities of 5 mA cm-2 and 20 mA cm-2, respectively. The assembled ZnSe⋅0.5N2H4@Zn||NH4V4O10 full cell presents outstanding cycling stability and rate capability. This work highlights the key role of crystal phase control of protective layer for high-performance zinc anode.

Hydrogen-Bonded Ionic Co-Crystals for Fast Solid-State Zinc Ion Storage.

The development of new ionic conductors meeting the requirements of current solid-state devices is imminent but still challenging. Hydrogen-bonded ionic co-crystals (HICs) are multi-component crystals based on hydrogen bonding and Coulombic interactions. Due to the hydrogen bond network and unique features of ionic crystals, HICs have flexible skeletons. More importantly, anion vacancies on their surface can potentially help dissociate and adsorb excess anions, forming cation transport channels at grain boundaries. Here, it is demonstrated that a HIC optimized by adjusting the ratio of zinc salt and imidazole can construct grain boundary-based fast Zn2+ transport channels. The as-obtained HIC solid electrolyte possesses an unprecedentedly high ionic conductivity at room and low temperatures (≈11.2 mScm-1 at 25°C and ≈2.78mScm-1 at -40°C) with ultra-low activation energy (≈0.12eV), while restraining dendrite growth and exhibiting low overpotential even at a high current density (<200mV at 5.0mAcm-2) during Zn symmetric cell cycling. This HIC also allows solid-state Zn||covalent organic framework full cells to work at low temperatures, providing superior stability. More importantly, the HIC can even support zinc-ion hybrid supercapacitors to work, achieving extraordinary rate capability and a power density comparable to aqueous solution-based supercapacitors. This work provides a path for designing facilely prepared, low-cost, and environmentally friendly ionic conductors with extremely high ionic conductivity and excellent interface compatibility.

Graphene-assisted improve electrochemical performance of manganese vanadium oxide for aqueous zinc-ion battery

Layer spacing of vanadium oxide can be effectively expanded by metal ion, however, its conductivity and electrochemical kinetics still require improvement. This work expands the layer spacing using manganese ion and help to improve conductivity and electrochemical kinetics by graphene. The results demonstrate that the layer spacing can be adjusted from 12.1 Å for pristine vanadium oxide (VOH) to 13.6 Å for manganese vanadium oxide (MnVO). Due to graphene introduction, it decreases to 11.6 Å for manganese vanadium oxide/graphene composite (MnVO-0.05–8/GN-15). Notably, the optimized composite delivers higher specific capacity of 507.5 mAh g−1 for MnVO-0.05–8/GN-15 than that of MnVO (410.4 mAh g−1) and VOH (370.1 mAh g−1) at current density of 0.5 A g−1. Furthermore, the MnVO-0.05–8/GN-15 exhibits fast Zn2+ ion diffusion ability, achieving high energy density of 403.51 Wh kg−1 and retaining an excellent cycle stability of 85.7% after 2000 cycles at a current density of 3 A g−1.

Aerogel‐Driven Interface Rapid Self‐Gelation Enables Highly Stable Zn Anode

AbstractThe practical application of Zn metal anodes is currently hindered by uncontrolled dendritic growth and water‐induced parasitic reactions that are closely related to the solvation structure and interfacial transport kinetics of Zn2+. Herein, a facile interface self‐gelation strategy is proposed to stabilize Zn anode by introducing ‐OH‐rich silica aerogel (HSA) on Zn anode surface. The unique interconnected network structure and strong hydrophilia of HSA made the aqueous electrolyte near Zn anode gel rapidly and spontaneously, resulting in the formation of a water‐poor gel interface layer. The interface layer can effectively accelerate the desolvation process and reduce water molecule activity near anode surface through hydrogen bonding interaction, thus achieving rapid Zn migration kinetics and alleviating side reactions. In addition, the well‐defined aerogel nanochannels can provide a fast Zn2+ migration path and homogenize Zn2+ flux, enabling rapid and uniform Zn deposition. As a result, the HSA‐modified Zn (HSA@Zn) anode exhibits excellent long‐term cycling stability (over 6000 h at 4 mA cm−2), and the feasibility for practical application of this HSA@Zn anode is further demonstrate in full cells. The aerogel‐driven interface self‐gelation strategy propose in this work provides new insights into the design of advanced Zn anode for aqueous zinc‐ion batteries.

Electrostatic adsorption driven self-assembly of V2O5·4VO2 nanoribbons and MXene for fast and stable Zn2+ storage

Electrostatic adsorption driven self-assembly of V2O5·4VO2 nanoribbons and MXene for fast and stable Zn2+ storage

Polyoxometalate Initiated In situ Conformal Coating of Multifunctional Hybrid Artificial Layers for High Performance Zinc Metal Anodes

AbstractAqueous zinc (Zn) metal batteries are very attractive owing to the high theoretical capacity (820 mAh g−1), meritable electrode potential (−0.76 V vs SHE), low cost, and environmental friendliness of Zn metal anodes. However, the dendrite formation, corrosion, and water decomposition on Zn metal anodes should be resolved for their practical applications. Herein, conformally coated multifunctional organic/inorganic hybrid artificial layers are demonstrated for the reversible and stable Zn deposition. These hybrid layers are synthesized through polyoxometalate (POM) initiated polymerization into poly(1,3‐dioxolane) (Poly(DOL)) and directly coated onto the Zn surface. Moreover, POM acted as chemical bridge connecting Poly(DOL) with Zn metal anode to construct mechanically robust layers with a thickness of ≈40 nm. The fast and selective Zn2+ ion transport of multifunctional POM/Poly(DOL) hybrid layer (POMDOL) and their preferential growth into (002) crystalline plane are attributed to the reversible Zn deposition. Accordingly, POMDOL coated Zn (PDOLZn) anodes achieves an extended cycling period up to 2,876 hours with a cumulative capacity of 29 Ah g−1 at 20 mA cm−2 and 1 mAh cm−2. Moreover, depth of discharge (DOD) of 40% is achieved. Consequently, the PDOLZn || β‐MnO2 full cells delivered the high specific capacity of 245 mAh g−1 and long‐term stability over 1 000 cycles.

An artificial sulfonated polyaniline coating for high stable and dendrite-free zinc anode

Designing the performance of artificial solid electrolyte interphase (ASEI) is critical for addressing issues at the Zn anode-electrolyte of aqueous zinc batteries (AZBs). Inspired by the anti-corrosion strategy of metal substrate, a self-doping sulfonated polyaniline (S-PANI) is constructed on the surface of zinc foil by a facile scraping method. The synergistic effect of nitrogen and sulfonic acid groups in S-PANI coating layer, accompanies microchannels in the polymer network is favorable for the fast Zn2+ ion transport, uniform and stable Zn deposition. As a result, the Zn anode with S-PANI coating can achieve high average coulombic efficiency of 98.0% over 150 cycles and superior cycling performance up to 1500 h at a 0.5 mA cm-2 and 0.5 mAh cm-2. Moreover, the full battery coupled with PTO organic cathode also demonstrates superior cycling stable performance. This work opens effective approach for the application of conductive polymer coating in Zn anode protection.

Tailored crystal planes of VO2 cathode power fast Zn2+ storage

Vanadium dioxide (VO2) cathode with specific tunnel structure and favorable specific capacity is critical for developing aqueous zinc-ion batteries (AZIBs) with excellent electrochemical performance. However, sluggish electrochemical kinetics hampered its development in burgeoning energy storage devices. Herein, we tailored VO2 material with different exposed crystal planes and employed as cathodes for AZIBs. The comprehensive analyses indicate the exposed (201) and (001) crystal planes are favorable for fast electrochemical kinetics, high capacitance storage, and the smallest diffusion energy barrier, which guarantee electrodes with high discharge capacity (367 mA h/g at 0.1 A/g), excellent rate capability (281 mA h/g at 4 A/g) and cycling stability over 800 cycles. Besides, Ex-situ characterizations manifest VO2 cathode with specific exposed crystal planes easily transformed to Zn3+x(OH)2V2O7·2H2O in the first discharge process, hence allowing continuous embedding of Zn2+ in this layered structure, and the ex-situ scanning electron microscopy (SEM) analysis confirms the morphology change matched well with the structural transformation. This study may enlighten and promote the role of exposed crystal plane to develop high-performance rechargeable batteries.

Electrolyte Stabilizes Zn2+ Reduction Reaction Process: Solvation, Interface and Kinetics

AbstractAqueous zinc‐ion batteries (ZIBs), lauded for their low cost, eco‐friendliness, and high safety, have garnered significant attention. However, their commercial viability is hindered by the challenges of dendrite growth and side reactions during the Zn2+ reduction reaction process. Electrolyte as the indispensable component of batteries has a close relationship with the issues mentioned above. With the feature of simplicity, effectiveness, and scalability, regulating electrolytes is a particularly promising, feasible, and straightforward approach to stabilizing the Zn anode. The solvation design with less solvated water, interface optimization with water‐poor and pH‐stable interface, and kinetics regulation with fast Zn2+ transport, uniform Zn2+ flux, and orientational Zn growth can contribute to uniform Zn deposition with restrained corrosion. This review encapsulates the cutting‐edge advancements in electrolytes to stabilize the Zn anode. The mechanisms underlying these advancements, encompassing solvation structure design, Zn‐electrolyte interface optimization, and kinetics regulation are elucidated. Finally, this paper outlines current challenges and prospects in electrolyte development for ZIBs, providing valuable insights for future endeavors in this field.

Stabilizing Zn anodes via a binder-free MoS2 interface with charge regulation toward stable Zinc-Ion batteries

Aqueous zinc ion batteries (AZIBs) have been a promising candidate for next-generation batteries. However, the uncontrolled dendrite formation and side reactions of the Zn anode significantly restrict their application. Herein, a binder-free MoS2 protective layer were uniformly deposited on Zn foil by electrochemical deposition. The MoS2 protected Zn anode has a lower nucleation barrier and a uniform electric field distribution, which can effectively alleviate the corrosion and side reactions of Zn metal, thus leading to the fast Zn2+ diffusion kinetics. The results show that the MoS2-Zn anode has low voltage hysteresis, long cycle stability at 0.5 mA cm−2/0.1 mAh cm−2 in symmetrical batteries. The MoS2-Zn//α-MnO2 full cell exhibits an exceptional reversible capacity of 225.8 mAh/g at 1C, while maintaining stable cycling performance over 300 cycles. This work provides a promising strategy to construct a 2D coating to improve the stability of Zn anode in AZIBs.

Conductive Zinc-Based Metal–Organic Framework Nanorods as Cathodes for High-Performance Zn-Ion Capacitors

Zinc-ion capacitors (ZICs), combining the merits of both high-energy zinc-ion batteries and high-power supercapacitors, are known as high-potential electrochemical energy storage (EES) devices. However, the research on ZICs still faces many challenges because of the lack of appropriate cathode materials with robust crystal structures and rich channels for stable and fast Zn2+ ion transport. In this study, we synthesized a robust, conductive, two-dimensional metal–organic framework (MOF) material, zinc-benzenehexathiolate (Zn-BHT), and investigated its electrochemical performance for zinc storage. Zn2+ ions could insert into/extricate from the host structure with a high diffusion rate, enabling the Zn-BHT cathode to exhibit a surface-controlled charge storage mechanism. Due to its unique structure, Zn-BHT exhibited a good reversible discharge capacity approaching 90.4 mAh g−1 at 0.1 A g−1, as well as a desirable rate capability and good cycling performance. In addition, a ZIC device was fabricated using the Zn-BHT cathode and a polyaniline-derived porous carbon (PC) anode, which depicted a high working voltage of up to 1.8 V and a high energy density of ~37.2 Wh kg−1. This work shows that conductive MOFs are high-potential electrode materials for ZICs and provide new enlightenment for the development of electrode materials for EES devices.

Functional Aerogel Driven Synchronous Modulation of Zn2+ Interfacial Migration Behavior and Electrolyte Microenvironment Enables Highly Reversible Zn Anodes

AbstractUncontrolled dendrite growth and electrolyte‐induced intricate parasitic reactions are two great challenges that hinder the commercial applications of aqueous zinc‐ion batteries. Herein, a synchronous modulation strategy for Zn2+ interfacial migration behavior and electrolyte microenvironment is proposed by constructing a functional lanthanum hydroxide aerogel (LAG) interface layer on Zn anode surface. The in situ derivation of ion‐conducting zinc hydroxide sulfate (ZHS) from LAG layer results in the spontaneous generation of a hierarchic interface layer during the plating process, where the high Zn2+ selectivity of the upper dense ZHS layer can limit SO42− migration and allow for fast Zn2+ interfacial migration kinetics, while the aerogel layer with well‐defined nanochannels near the anode side can homogenize Zn2+ distribution, thus leading to the effective suppression of both dendrites and side reactions. Additionally, the pH microenvironment of the acidic electrolyte can be synchronously regulated by slightly soluble La(OH)3 aerogel, further inhibiting electrolyte corrosion and HER. Consequently, the modified Zn anode delivers highly reversible Zn plating/stripping and low‐voltage hysteresis, and the high areal‐capacity Zn||MnO2 full cells demonstrate considerable electrochemical performances under high Zn utilization conditions. This functional aerogel‐driven synchronous modulation strategy of Zn2+ migration behavior and electrolyte microenvironment provides new insight for stabilizing Zn metal anodes.

Multi-metal ions co-regulated vanadium oxide cathode toward long-life aqueous zinc-ion batteries

Interlayer intercalation engineering shows great feasibility to improve the structure stability of the layered oxides. Although high Zn-storage capability has been attained based on the pillar effect of multifarious intercalants, an in-depth understanding the synergistic effect of intercalated multiple metal ions is still in deficiency. Herein, alkali metal ion K+, alkaline earth metal ion Mg2+ and trivalent metal ion Al3+ are introduced into the VO interlayer of V2O5. Due to the different electronegativity and hydrated ion radius of K+, Mg2+ and Al3+, adjusting the relative proportions of these metal ions can achieve an appropriate interlayer spacing, stable layer structure and regular morphology, which facilitates the transport kinetics of Zn2+. Under the synergistic effect of pre-intercalated multi-metal ion, the optimal tri-metal ion intercalated hydrated V2O5 cathode exhibits a high specific capacity of 382.4 mAh g−1 at 0.5 A g−1, and long-term cycling stability with capacity retention of 86 % after 2000 cycles at the high current density of 10 A g−1. Ex-situ and kinetic characterizations reveal the fast charge transfer and reversible Zn2+ intercalation mechanism. The multi-ion engineering strategy provides an effective way to design desirable layered cathode materials for aqueous zinc-ion batteries.

Reconstruction of Electric Double Layer on the Anode Interface by Localized Electronic Structure Engineering for Aqueous Zn Ion Batteries

AbstractThe electric double layer (EDL) at the electrode/electrolyte interface plays a crucial role to the electrochemical reactions of zinc ion batteries. For Zn anode, the EDL consists of H2O dipoles, which can cause Zn corrosion and passivation. Herein, the localized electronic‐rich (LER) structure performing as soild electrolyte interphase (SEI) changes the electron distribution, leading to the rapid capture of Zn2+, thus promoting the desolvation of the cH2O shell. Moreover, the LER generates an electrostatic repulsion effect to SO42−. Consequently, a unique H2O‐poor EDL is reconstructed with the distribution of Zn2+‐H2O‐SO42−, which inhibits side reactions and improves the deposition kinetics of Zn2+. In situ Raman intuitively confirms that the zinc‐ion‐flux is uniform during the whole electroplating process. LER as regulator for EDL structure, leads to smooth and fast Zn2+ deposition. The performance enhancement is demonstrated by LER@Zn//LER@Zn cells, which exhibit exceptional lifespan for 4800 h. Furthermore, the LER@Zn///MnO2 cell shows improved cycling stability over 1500 cycles, with a high capacity of 124 mAh g−1 at 5 C.

Ethanol as Solvent Additives with Competitive Effect for High-Stable Aqueous Zinc Batteries.

Aqueous zinc-ion batteries are emerging as promising sustainable energy-storage devices. However, their cyclic stability is still a great challenge due to the inevitable parasitic reaction and dendrite growth induced by water. Herein, a cosolvent strategy based on competitive effect is proposed to address the aforementioned challenges. Ethanol with a higher Gutmann donor number demonstrates lower polarity and better wettability on the Zn surface compared with water, which endows ethanol with the ability of minimizing water activity by weakening H bonds and preferentially adsorbing on the Zn electrode. The above competitive advantages synergistically contribute to inhibiting the decomposition of free water and dendrite growth. Besides, an organic-inorganic hybrid solid-electrolyte interphase layer is in situ built based on ethanol additives, where organic matrix suppresses water corrosion while inorganic fillers promote fast Zn2+ diffusion. Consequently, the electrolyte with ethanol additives boosts a high reversibility of Zn deposition, long-term durability, as well as superior Zn2+ diffusibility in both Zn half-cells (Zn||Cu and Zn||Zn batteries) and Zn full cells (Zn||PTCDA and Zn||VO2 batteries). This work sheds light on a universal strategy to design a high-reversible and dendrite-free Zn anode for stable aqueous batteries.

Building stabilized Cu0.17Mn0.03V2O5−□·2.16H2O cathode enables an outstanding room‐/low‐temperature aqueous Zn‐ion batteries

AbstractVanadium oxide cathode materials with stable crystal structure and fast Zn2+ storage capabilities are extremely important to achieving outstanding electrochemical performance in aqueous zinc‐ion batteries. In this work, a one‐step hydrothermal method was used to manipulate the bimetallic ion intercalation into the interlayer of vanadium oxide. The pre‐intercalated Cu ions act as pillars to pin the vanadium oxide (V‐O) layers, establishing stabilized two‐dimensional channels for fast Zn2+ diffusion. The occupation of Mn ions between V‐O interlayer further expands the layer spacing and increases the concentration of oxygen defects (Od), which boosts the Zn2+ diffusion kinetics. As a result, as‐prepared Cu0.17Mn0.03V2O5−□·2.16H2O cathode shows outstanding Zn‐storage capabilities under room‐ and low‐temperature environments (e.g., 440.3 mAh g−1 at room temperature and 294.3 mAh g−1 at −60°C). Importantly, it shows a long cycling life and high capacity retention of 93.4% over 2500 cycles at 2 A g−1 at −60°C. Furthermore, the reversible intercalation chemistry mechanisms during discharging/charging processes were revealed via operando X‐ray powder diffraction and ex situ Raman characterizations. The strategy of a couple of 3d transition metal doping provides a solution for the development of superior room‐/low‐temperature vanadium‐based cathode materials.

Nitroxyl radical triggered the construction of a molecular protective layer for achieving durable Zn metal anodes

The issues of dendrite growth, hydrogen evolution reaction, and zinc anode corrosion have significantly hindered the widespread implementation of aqueous zinc-ion batteries (AZIBs). Herein, trace amounts of 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) additive is introduced into AZIBs to protect the zinc metal anode. Trace amounts of the TEMPO additive with nitroxyl radical can provide fast Zn2+ transport and anode protection ability by forming an adsorbed molecular layer via Zn-O bond. This interface not only provides strong interfacial compatibility and promotes dynamic transport of Zn2+, but also induces deposition of Zn2+ along Zn (002) plane. Additionally, the molecular protective layer significantly inhibits hydrogen evolution reaction (HER) and corrosion. The Zn anodes achieve high Coulombic efficiency of up to 99.75 % and long-term plating/stripping of more than 1400 h at 1 mA cm−2 and 0.5 mAh cm−2. The Zn//Zn symmetric cell can operate continuously for 2500 h at a current density of 1 mA cm−2 and 1 mAh cm−2, and it can still last for nearly 1400 h even when the current density is increased to 5 mA cm−2. Furthermore, the Zn//V2O5 full cell using TEMPO/ZnSO4 electrolyte effectively maintains a maximum capacity retention rate of 53.4 % even after 1500 cycles at 5 A/g. This innovative strategy introduces trace additive with free radicals into the electrolyte, which may help to achieve large-scale, ultra-long-life, and low-cost AZIBs.

Self-supporting nickel-doped V2O5 nanoarrays as bifunctional electrodes for wearable aqueous zinc-ion batteries and pressure sensors

Vanadium pentoxide (V2O5), due to its distinctive open-framework construction and significant theoretical capacity, has widespread applications in the rapid development of aqueous zinc-ion batteries (AZIBs) and pressure sensors. However, V2O5 exhibits rapid capacity degradation and poor cycling stability due to its low electrical conductivity and ion diffusion rate, limiting its vast application prospects. Therefore, the self-supporting V2O5 nanoarrays employing a Ni doping strategy on flexible carbon substrates act as an AZIBs cathode material (Ni–V2O5@CNTF), which possesses an enlarged interlayer space and high ion conductivity to provide a stable crystal structure for fast and reversible Zn2+ insertion/extraction. More notably, the assembled Zn/Ni–V2O5@CNTF battery achieves a high capacity of 398.85 mAh cm−3 at 0.1 A cm−3, superior rate performance and cycling stability for 2000 cycles. In addition, the V2O5 nanoarrays grown on carbon cloth serving as the functional electrode material (Ni–V2O5@CC) are applied in a flexible resistive pressure sensor, exhibiting a high sensitivity of 0.8 kPa−1 from 0 to 5.0 kPa and stable sensing capabilities from 0 to 25 kPa. Furthermore, extensive applications are investigated in monitoring human activities and anti-intrusion pre-alarm systems. This work demonstrates a dual-functional fabric electrode based on Ni–V2O5, offering new guidelines for the next generation of multifunctional flexible electronic products.

Component Fluctuation Modulated Gelation Effect Enable Temperature Adaptability in Zinc‐Ion Batteries

AbstractThe active H2O and slow ion kinetics behavior deteriorate the performance of aqueous zinc‐ion batteries at a wide temperature range, even in hydrogel electrolyte. Herein, a component fluctuation modulated gelation effect is applied to optimize Zn2+ solvation structure, realizing a balance between H2O activity limitation and Zn2+ kinetics retention. The as‐prepared hydrogel electrolyte via in situ copolymerization of [2‐(methacryloyloxy)ethyl] dimethyl‐(3‐sulfopropyl) and acrylamide in the electrolyte salt matrix facilitates stable overall performance at both normal and low temperatures. Theoretical calculations and experimental results attest that polymer functional groups exhibit a higher efficacy in substituting bound water in the Zn2+ solvated shell with the polymer content increasement, thereby alleviating water‐associated parasitic reactions. Furthermore, the hydrogel with abundant zwitterionic groups not only interacts with H2O to limit hydrolysis, but also constructs separated ionic migration channels to promote uniform and fast Zn2+ transport. As a result, the hydrogel electrolytes promote stable Zn2+ plating/stripping behaviors over 1050 h and 3000 h at 25 and −20 °C, respectively. The full batteries achieve a capacity retention of 98.8% over 2000 cycles at 25 °C and stably cycle for 600 times at −20 °C. This work yields novel insights into the development and design of hydrogel electrolytes.

Tandem Chemistry with Janus Mesopores Accelerator for Efficient Aqueous Batteries.

A reliable solid electrolyte interphase (SEI) on the metallic Zn anode is imperative for stable Zn-based aqueous batteries. However, the incompatible Zn-ion reduction processes, scilicet simultaneous adsorption (capture) and desolvation (repulsion) of Zn2+(H2O)6, raise kinetics and stability challenges for the design of SEI. Here, we demonstrate a tandem chemistry strategy to decouple and accelerate the concurrent adsorption and desolvation processes of the Zn2+ cluster at the inner Helmholtz layer. An electrochemically assembled perforative mesopore SiO2 interphase with tandem hydrophilic -OH and hydrophobic -F groups serves as a Janus mesopores accelerator to boost a fast and stable Zn2+ reduction reaction. Combining in situ electrochemical digital holography, molecular dynamics simulations, and spectroscopic characterizations reveals that -OH groups capture Zn2+ clusters from the bulk electrolyte and then -F groups repulse coordinated H2O molecules in the solvation shell to achieve the tandem ion reduction process. The resultant symmetric batteries exhibit reversible cycles over 8000 and 2000 h under high current densities of 4 and 10 mA cm-2, respectively. The feasibility of the tandem chemistry is further evidenced in both Zn//VO2 and Zn//I2 batteries, and it might be universal to other aqueous metal-ion batteries.