In-situ electrochemical modification of pre-intercalated vanadium bronze cathodes for aqueous zinc-ion batteries
Jianwei Li, Ningyun Hong, Ningjing Luo, Haobo Dong, Liqun Kang, Zhengjun Peng, Guofeng Jia, Guoliang Chai, Min Wang, Guanjie He
Abstract
Abstract Vanadium bronzes have been well-demonstrated as promising cathode materials for aqueous zinc-ion batteries. However, conventional single-ion pre-intercalated V 2 O 5 nearly reached its energy/power ceiling due to the nature of micro/electronic structures and unfavourable phase transition during Zn 2+ storage processes. Here, a simple and universal in-situ anodic oxidation method of quasi-layered CaV 4 O 9 in a tailored electrolyte was developed to introduce dual ions (Ca 2+ and Zn 2+ ) into bilayer δ-V 2 O 5 frameworks forming crystallographic ultra-thin vanadium bronzes, Ca 0.12 Zn 0.12 V 2 O 5 · n H 2 O. The materials deliver transcendental maximum energy and power densities of 366 W h kg −1 (478 mA h g −1 @ 0.2 A g −1 ) and 6627 W kg −1 (245 mA h g −1 @ 10 A g −1 ), respectively, and the long cycling stability with a high specific capacity up to 205 mA h g −1 after 3000 cycles at 10 A g −1 . The synergistic contributions of dual ions and Ca 2+ electrolyte additives on battery performances were systematically investigated by multiple in-/ex-situ characterisations to reveal reversible structural/chemical evolutions and enhanced electrochemical kinetics, highlighting the significance of electrolyte-governed conversion reaction process. Through the computational approach, reinforced “pillar” effects, charge screening effects and regulated electronic structures derived from pre-intercalated dual ions were elucidated for contributing to boosted charge storage properties.