Weaker Interactions in Zn^(2+)and Organic Ion-pre-intercalated Vanadium Oxide toward Highly Reversible Zinc-ion Batteries

摘要

Driven by safety issues,environmental concerns,and high costs,rechargeable aqueous zinc-ion batteries(ZIBs)have received increasing attention in recent years owing to their unique advantages.However,the sluggish kinetics of divalent charge Zn^(2+)in the cathode materials caused by the strong electrostatic interaction and their unsatisfactory cycle life hinder the development of ZIBs.Herein,organic cations and Zn^(2+)ions co-pre-inserted vanadium oxide([N(CH_(3))_(4)]_(0.77),Zn_(0.23))V_(8)O_(20)·3.8H_(2)O are reported as the cathode for ultra-stable aqueous ZIBs,in which the weaker electrostatic interactions between Zn^(2+)and organic ion-pinned vanadium oxide can induce the high reversibility of Zn^(2+)insertion and extraction,thereby improving the cycle life.It is demonstrated that([N(CH_(3))_(4)]_(0.77),Zn_(0.23))V_(8)O_(20)·3.8H_(2)O cathodes deliver a discharge capacity of 181 mA h g^(-1)at8 A g^(-1)and ultra-long life span(99.5%capacity retention after 2000 cycles).A reversible Zn^(2+)/H^(+)ions(de)intercalation storage process and pseudocapacitive charge storage are characterized.The weaker interactions between organic ion and Zn^(2+)open a novel avenue for the design of highly reversible cathode materials with long-term cycling stability.