A High-Performance Aqueous Zinc-Thiocyanogen-Iodine Battery with High Capacity and Dual Platforms

Aqueous zinc-iodine batteries (AZIBs) have emerged as promising energy storage devices owing to their advantages of low cost, inherent safety and environmental friendliness. However, most AZIBs primarily operate through a single <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathrm{I}^{0}/\mathrm{I}^{-}$</tex> redox reaction, which results in constrained operating voltage and capacity. Recently, the four-electron conversion mechanism of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathrm{I}^{+}/\mathrm{I}^{0}/\mathrm{I}^{-}$</tex> has been activated to solve these issues, yet this process encounters challenges such as intricate cross side reactions. Herein, high-capacity and dual-platform Zn-(SCN)2-12 batteries (ZSIBs) have been prepared by introducing a water-in-salt (WIS) electrolyte system with <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\text{I-}$</tex> and <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\text{SCN}^{-}$</tex>. The introduction of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathrm{V}_{2}\text{CT}_{\mathrm{x}}$</tex> MXene effectively inhibited the side-reaction and shuttle effects present in ZSIBs, demonstrated a discharge specific capacity of 806.4 <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mu \text{Ahcm}^{-2}(290\text{mAhg}^{-1})$</tex>, the device can retain 97.84% in 500 charge/discharge cycles. Additionally, the combination of oxygen-enriched carbon(ACC) and <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathrm{V}_{2}\text{CT}_{\mathrm{x}}$</tex> MXene enabling a high discharge specific capacity of 2995.8 <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mu \text{Ahcm}^{-2}$</tex> and energy density of 3.60 <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\text{mWhcm}^{-2}$</tex>, thereby shedding new light on the design and development of aqueous Zn-ion batteries.