High-performance Zn-ion Batteries Research Articles

K-preintercalated MnO2 nanosheets as cathode for high-performance Zn-ion batteries

Manganese oxides are regarded as promising cathode materials for aqueous zinc ion batteries (ZIBs) due to their low cost and high theoretical capacity. However, their practical application is seriously hindered because of the inferior electronic conductivity, sluggish diffusion kinetics and structural instability. Herein, we develop a new K-preintercalated MnO 2 (K 0.19 MnO 2 ·0.56H 2 O, KMO) nanosheet by a facile hydrothermal method. Preintercalation of K + ions into the MnO 2 crystal layers with structural reconstruction can activate more active sites, strengthen the crystal structural stability and facilitate the insertion/extraction of Zn 2+ ions. The charge shielding effect of crystal water promotes the diffusion kinetics of Zn 2+ ions. The obtained KMO electrode delivers high specific capacity (107 mAh g −1 ) and good cycling stability (~87.5% capacity retention after 2000 cycles), revealing its potential application for aqueous ZIBs.

Ultra-Fast and Scalable Saline Immersion Strategy Enabling Uniform Zn Nucleation and Deposition for High-Performance Zn-Ion Batteries.

Although aqueous Zn-ion batteries (ZIBs) with low cost and high safety show great potential in large-scale energy storage system, metallic Zn anode still suffers from unsatisfactory cycle stability due to unregulated growth of Zn dendrites, corrosion, and formation of various side products during electrochemical reaction. Here, an ultrafast and simple method to achieve a stable Zn anode is developed. By simply immersing a Zn plate into an aqueous solution of CuSO4 for only 10-60 s, a uniform and robust protective layer (Zn4 SO4 (OH)6 ·5H2 O/Cu2 O) is formed on commercial Zn plate (Zn/ZCO), which enables uniform electric field distribution and controllable dendrite growth, leading to a long-term cycle life of over 1400 h and high average Coulombic efficiency (CE) of 99.2% at 2.0mA cm-2 and 2.0 mAh cm-2 . These excellent characteristics of the prepared Zn anode show great potential in practical applications for high-performance aqueous Zn-ion batteries.

Sulfonic-Group-Grafted Ti3C2Tx MXene: A Silver Bullet to Settle the Instability of Polyaniline toward High-Performance Zn-Ion Batteries.

Polyaniline (PANI) is a promising cathode material for Zn-ion batteries (ZIBs) due to its intrinsic conductivity and redox activity; however, the achievements of PANI in high-performance ZIBs are largely hindered by its instability during the repeated charge/discharge. Taking advantage of the high conductivity, flexibility, and grafting ability together, a surface-engineered Ti3C2Tx MXene is designed as a silver bullet to fight against the deprotonation and swelling/shrinking issues occurring in the redox process of PANI, which are the origins of its instability. Specifically, the sulfonic-group-grafted Ti3C2Tx(S-Ti3C2Tx) continuously provides protons to improve the protonation degree of PANI and maintains the polymer backbone at a locally low pH, which effectively inhibits deprotonation and brings high redox activity along with good reversibility. Meanwhile, the conductive and flexible natures of S-Ti3C2Tx assist the fast redox reaction of PANI and concurrently buffer its corresponding swelling/shrinking. Therefore, the S-Ti3C2Tx-enhanced PANI cathode simultaneously achieves a high discharge capacity of 262 mAh g-1 at 0.5 A g-1, a superior rate capability of 160 mAh g-1 at 15 A g-1, and a good cyclability over 5000 cycles with 100% coulombic efficiency. This work enlightens the development of versatile MXene via surface engineering for advanced batteries.

Molten salt strategy and plasma technology induced MnO2 with oxygen vacancy for high performance Zn-ion batteries

The oxygen vacancy-rich MnO2 was synthesized by the molten salt method and the plasma etching strategy. The amorphous layer increased the active sites and the oxygen vacancies on the surface of MnO2 that promoted the rapid transfer of charges.

A liquid metal assisted dendrite-free anode for high-performance Zn-ion batteries

A self-healing zinc anode is achieved by introducing a liquid Ga–In–Zn alloy as a protective layer on zinc foil. The high fluidity and deformability of the liquid alloy ensure an ultralong cycling life by enabling dendrite-free Zn deposition.

Cu-MOF-derived and porous Cu0.26V2O5@C composite cathode for aqueous zinc-ion batteries

One fundamental issue for developing high-performance Zn-ion batteries (ZIBs) is the exploration of stable and efficient cathode materials that can reversibly intercalate zinc ions at a high capacity and potential. Layered vanadium oxides have been regarded as a suitable candidate for this purpose due to their high zinc-ion storage capacity. However, the sluggish kinetics of zinc-ion intercalation/deintercalation and the poor conductivity of vanadium oxides are still the bottle bottlenecks that impede the further enhancement of their performance for ZIBs. Addressing this issue, we herein demonstrate a direct impregnation and conversion strategy to prepare a Cu-doped V2O5 and hierarchical porous carbon (Cu0.26V2O5@C) composite as the cathode for ZIBs. In this protocol, the Cu doping can promote the zinc-ion migration by broadening and stabilizing the layered structure of V2O5, the hierarchical porosity can enlarge the contact between the active material and the electrolyte to achieve efficient infiltration of the electrolyte into the material, while the carbon host can improve the electronic conductivity. The combination of these merits thus delivers a high specific capacity (328.8 mAh g−1 at 0.2 A g−1), high rate performance (163.8 mAh g−1 at 2 A g−1), and excellent long-term cyclic stability with 93.5% capacity retention after 500 cycles.

Tuning Zn2+ coordination environment to suppress dendrite formation for high-performance Zn-ion batteries

The short-circuit issue induced by Zn dendrite growth restricts the commercialization of rechargeable aqueous Zn-ion batteries (ZIBs). Herein, ethylene glycol (EG), a representative of dihydric alcohols, is applied in the aqueous electrolyte to inhibit the detrimental dendrite growth on Zn anode. Our work demonstrates a uniform Zn plating/stripping in H2O/EG hybrid electrolyte with cycling lifespan of up to 2668 h at 0.5 mA cm−2, which is made possible by the substitution of EG for H2O in the solvation sheath of Zn2+ ions. Such a change in the coordination environment of Zn2+ gives rise to decreased diffusivity of the ions and increased over-potential for nucleation, further resulting in even deposition morphology rather than large-scale dendrites. Side reactions are also circumvented by the formation of hydrogen bonds. All these aspects work in synergy to promote the cyclability of the assembled full battery. The low-cost aqueous electrolyte identified in this work opens up new opportunities for manipulating the coordination environments of Zn2+ ions and optimizing the Zn deposition morphology during the design of high-performance ZIBs.

Engineering stable Zn-MnO2 batteries by synergistic stabilization between the carbon nanofiber core and birnessite-MnO2 nanosheets shell

Aqueous Zn/MnO2 batteries have attracted considerable attention for large-scale energy storage application owing to their low cost, high safety and environmental friendliness. However, MnO2 cathodes still suffer from the inferior utilization and deficient cyclability at a wide range of current densities. Integrating MnO2 with conductive carbon is promising to overcome the challenges. Unfortunately, the required use of strongly oxidative acids or expensive plasma to functionalize the inherently hydrophobic carbon makes it an obstacle for scalable production. Herein, the hierarchical core-shell carbon nanofiber(CNF)@MnO2 (MOC) nanowires were synthesized by using a facile, controllable and scalable approach combining simple grinding and low-temperature wet-chemical reaction. A synergistic effect was demonstrated for the MOC cathode in Zn-ion batteries (ZIBs). The conductive CNF backbone significantly boosts the electron transfer kinetics, while ultrathin MnO2 nanosheets provide large electrode/electrolyte interfacial contact areas and facilitate the ionic diffusion. Additionally, the intimate contact between CNFs and MnO2 synergistically renders an interconnected network with high electronic and ionic conductivity and flexibility to minimize structural collapse and strain of volume variation upon cycling. The favorable synergistic effect ensures the high capacity, long shelf life, enhanced rate capability and extraordinary cycling stability of MOC. It shows a high capacity of 221 mAh g−1 after 700 cycles at 200 mA g−1. Even at 3000 mA g−1, it still maintains 130 mAh g−1 after 2750 cycles without obvious capacity decay. Featuring the exceptional electrochemical performance, rational design for synergy and low-cost manufacturing, the developed MOC cathode is promising for cost-efficient and high-performance ZIBs.

Mechanistic investigation of silver vanadate as superior cathode for high rate and durable zinc-ion batteries

Rechargeable aqueous Zn-ion batteries have shown considerable potential for stationary grid-scale energy storage systems owing to their characteristics of low cost and non-pollution. Nevertheless, the development of high-performance cathode materials is still a formidable challenge. In this work, for the first time, we report a superior silver vanadate (β-AgVO3) cathode for Zn-ion batteries, and demonstrate the fundamental Zn2+ storage mechanism in detail. In sharp contrast to the previously-reported layered vandium-based materials, the β-AgVO3 cathode experiences an initial phase transition to form a layered Zn3V2O7(OH)2·2H2O through a displacement/reduction reaction of Zn2+/Ag+ in the first discharge process. The in situ generated Ag0 along with the residual Ag+ and structural water within the framework afford high electronic/ionic conductivity, thus enabling enhanced Zn2+ intercalation/deintercalation kinetics in the layered phase. As a consequence, the cathode can deliver remarkable rate performance (103 mAh g−1 at 5000 mA g−1) and long-term cycling stability (95 mAh g−1 after 1000 cycles at 2000 mA g−1). The present study offers a totally new insight into the exploration of non-layered-structured vandium-based cathodes for high performance Zn-ion batteries.

Realizing high-performance Zn-ion batteries by a reduced graphene oxide block layer at room and low temperatures

Abstract Rechargeable aqueous Zn-ion batteries (ZIBs) have attracted great attention due to their cost-effectiveness, high safety, and environmental friendliness. However, some issues associated with poor structural instability of cathode materials and fast self-discharge hinder the further development of ZIBs. Herein, a new configuration is introduced by placing a reduced graphene oxide film as a block layer between the separator and the V2O5·nH2O cathode. This layer prevents the free diffusion of dissolved active materials to the anode and facilitates the transport of Zn ion and electrons, largely improving the cyclic stability and alleviating the self-discharge. Accordingly, the optimized battery delivers a remarkable capacity of 191 mAh g−1 after 500 cycles at 2 A g−1. Moreover, a high capacity of 106 mAh g−1 is achieved after 100 cycles at −20 °C. The strategy proposed is expected to be applicable to other electrode systems, thus offering a new approach to circumvent the critical challenges facing aqueous batteries.