Crystalline and amorphous Mn0_(2)cathodes with open framework enable high-performance aqueous zinc-ion batteries

摘要

Currently,δ-Mn0_(2)is one of the popularly studied cathode materials for aqueous zinc-ion batteries(ZIBs)but impeded by the sluggish kinetics of Zn^(2+)and the Mn cathode dissolution.Here,we report our discovery in the study of crystalline/amorphous Mn0_(2)(disordered Mn0_(2)),prepared by a simple redox reaction in the order/disorder engineering.This disordered Mn0_(2)cathode material,having open framework with more active sites and more stable structure,shows improved electrochemical performance in 2 mol L^(-1)ZnSO_(4)/0.1 mol L^(-1)MnS0_(4)aqueous electrolyte.It delivers an ultrahigh discharge specific capacity of 636 mA·h·g^(-1)at 0.1 A·g^(-1)and remains a large discharge capacity of 216 mA·h·g^(-1)even at a high current density of 1 A·g^(-1)after 400 cycles.Hence disordered Mn0_(2)could be a promising cathode material for aqueous ZIBs.The storage mechanism of the disordered Mn0_(2)electrode is also systematically investigated by structural and morphological examinations of ex situ,ultimately proving that the mechanism is the same as that of the δ-Mn0_(2)electrode.This work may pave the way for the possibility of using the order/disorder engineering to introduce novel properties in electrode materials for high-performance aqueous ZIBs.