2D VS 2 @MXene Based Zinc Ion Batteries with SPANI-Contained Electrolyte Enables Dendrite-Free Anode for Stable Cycling.

Regarded as one of the popular cathode materials in aqueous zinc ion batteries (ZIBs), VS 2 has unsatisfied cycling stability and relatively low capacity owing to its poor conductivity and low mechanical properties. To this regard, compositing VS 2 with high-conductive 2D transition metal carbide (MXene) has been an effective method recently. However, the Zn dendrite on the anode electrode derived from the uncontrollable sluggish migration of solvated Zn 2+ /H 2 O ions seriously threatens the application safety of ZIB batteries. To effectively regulate the diffusion of zinc ions, in this work a conductive polymeric electrolyte of sulfonated polyaniline (SPANI) is added in the electrolyte solution. Under the Zn 2+ /SPANI interactions confirmed by X-ray diffraction, Raman, and zeta potential experiments, the Zn 2+ /H 2 O combination is weakened, and the deposition rate of Zn 2+ is increased evaluated by the galvanostatic intermittent titration technique. Theoretical simulation shows that the electrostatic shielding by SPANI combining Zn 2- at the zinc/electrolyte interface has important contribution to the significant suppression of Zn dendrite. Accordingly, the fabricated VS 2 @MXene||ZnSO 4 +SPANI||Zn battery shows high capacity (368.0 mAh g -1 at 0.1 A g -1 ), which remains 96% after 5000 cyclic charge-discharge operations. This work develops an available strategic idea for suppressing growth of metallic dendrites to improve the ZIB performances.