High-performance aqueous zinc-ion batteries with air self-charging capability based on azo-based covalent organic frameworks.

Aqueous rechargeable zinc ion batteries are promising candidates for grid-scale applications owing to their low cost and high safety. However, they are plagued by the lack of suitable cathode and anode materials. Herein, we report on potassium vanadate (KVO) nanobelts as a promising cathode for an aqueous zinc ion battery, which shows a high discharge capacity of 461 mA h g-1 at 0.2 A g-1 and exhibits a capacity retention of 96.2% over 4000 cycles at 10 A g-1. Furthermore, to enhance the energy efficiency in an aqueous zinc ion battery, a facile and effective method on the anode is demonstrated. The energy efficiency increases from 47.5% for Zn//KVO coupled with the zinc foil anode to 66.5% for AB-Zn//KVO coupled with an acetylene black film improved zinc foil anode at 10 A g-1. The remarkable electrochemical performance makes AB-Zn//KVO a strong candidate for a high-performance aqueous zinc ion battery.

Aqueous rechargeable zinc-ion batteries (ZIBs) have attracted considerable attention as one of the most promising energy storage systems for the grid-scale application owing to the natural merits of metallic Zn, including a high theoretical capacity, suitable redox potential, low cost, high safety, and eco-friendliness. However, the existing aqueous ZIBs are far from satisfying the requirements of practical applications. Significant challenges hindering the further development of ZIBs come from the low utilization and poor cycling stability of cathodes and limited reversibility of Zn anodes associated with dendrite growth, corrosion, and passivation. To date, enormous efforts have been devoted to developing high-performance cathode materials, reliable electrolytes, and stable Zn anodes to achieve ZIB with high energy and power densities and long cycle life. These progresses have been reviewed in this dissertation. Regarding the main issues of ZIBs, the dissertation covered both the cathode and anode to comprehensively improve the electrochemical performance of ZIBs. For the cathode, high-performance manganese oxide-based cathode materials have been developed by in-situ electrochemical activation of MnS, and rational design of hierarchical core-shell MnO2@carbon nanofiber structures. To further understand the underlying reasons for the enhanced electrochemical performance, the charge storage mechanisms of manganese oxide-based cathodes in ZIBs have been in-depth investigated. With respect to the Zn anode, a thin polyvinyl alcohol (PVA) coating layer on the Zn anode has enabled dendrite-free, long-life aqueous Zn batteries by effectively regulating the interfacial ion diffusion and inducing the homogeneous Zn nucleation and deposition of stacked plates with preferentially crystallographic orientation along (002)Zn planes. This work is expected to provide facile and low-cost approaches for developing high-performance, cost-effective, and stable aqueous ZIBs and shed light on a new mechanistic understanding of manganese oxide-based cathodes.

Phosphate synergism activation strategy for amorphous vanadium oxide cathode materials of high-performance aqueous zinc ion batteries

Advances in application of sustainable lignocellulosic materials for high-performance aqueous zinc-ion batteries

Multifactor induction of pseudocapacitive in manganese oxide cathode enabling high-performance aqueous zinc ion batteries

Sodium ion stabilized ammonium vanadate as a high-performance aqueous zinc-ion battery cathode

Layered MnO2@PDA as cathode material toward high-performance aqueous zinc-ion batteries

Hierarchical spheroidal MOF-derived MnO@C as cathode components for high-performance aqueous zinc ion batteries

Insights on rational design and energy storage mechanism of Mn-based cathode materials towards high performance aqueous zinc-ion batteries

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

Hybridizing δ-type NaxV2O5·nH2O with graphene towards high-performance aqueous zinc-ion batteries

Up against the energy shortage and aggravating environmental pollution, it is extremely urgent to develop renewable clean energy. With efficient energy storage and energy conversion, electrochemical energy storage is the key direction for the development of energy storage technology in the future. Besides, aqueous zinc ion battery has attracted researchers because of its low cost and high theoretical specific capacity. Cathode materials for aqueous zinc ion batteries are roughly divided into manganese-based compounds, vanadium-based compounds, Prussian blue analogues, etc, which usually use zinc metal as an anode. Electrolytes include solid hydrogel electrolytes and liquid ion electrolytes. However, some problems exist in cathode materials, such as elements dissolution and low discharge voltage, while anode materials have problems in zinc dendrite growth and side reactions, and water decomposition occurs in electrolytes. In recent years, researchers have devoted themselves to optimizing aqueous zinc ion batteries in different ways, so as to obtain their high performance. In this paper, the general situation of zinc ion battery is introduced at first, and then the research status is emphatically expounded from the perspectives of problems existing in cathode materials, anode materials, electrolyte, and their optimization methods, which provides references for developing high-performance aqueous zinc ion battery.

Aqueous zinc ion batteries (AZIBs) hold great potential in large scale, low-cost energy storage. Unfortunately, their development is limited by the poor performing cathode materials due to their unstable structures and low capacities. Hence, we develop novel layer-by-layer stacked vanadium nitride nanocrystals/N-doped carbon hybrid nanosheets (VN/NC) as cathode materials by in situ thermal conversion of pyrolyzing pentyl viologen intercalated V2O5. The combination of a leaf-like morphology, the nano structure of vanadium nitride crystals and the conductive porous nitrogen-doped carbon nanosheets endow the VN/NC cathode with excellent electrochemical performance in AZIBs. Thus, it delivers a high discharge specific capacity of 566 mA h g-1 at a current density of 0.2 A g-1 and a superior rate capability. Most importantly, it exhibits a remarkable cyclic stability with capacity retention of 131 mA h g-1 (85% of the initial capacity) after 1000 cycles at a current density of 10 A g-1. The design of the unique VN/NC hybrid nano sheets offers a pathway towards developing high performance electrode materials for energy storage.

Construction of novel polyaniline-intercalated hierarchical porous V2O5 nanobelts with enhanced diffusion kinetics and ultra-stable cyclability for aqueous zinc-ion batteries

V-MOF@carbon nanotube derived three-dimensional V2O5@carbon nanotube as high-performance cathode for aqueous zinc-ion batteries