Crystallization and electrochemical properties of KVO nano-ribbons obtained a solvothermal process as a promising cathode for PIBs.

In this research, a series of K-intercalated quasi-1D vanadium-based nano-ribbons (KVO NRs) were synthesized a facile solvothermal method. The solvation and reductive effects of vanadium oxide precursors (VO powder) on the crystallization and growth of KVO NRs were studied. Besides, post-heat treatment was performed to improve the crystallinity of KVO NRs. These KVO NRs were adopted as active cathodes for potassium-ion batteries (PIBs), whose K storage properties were systematically evaluated using various electrochemical methods. The relationship among the morphology, crystallinity, working voltage window and electrochemical reversible K storage performance of KVO NRs was studied and established. Results reveal that KVO-HG, which was prepared a solvothermal reaction involving a solvation process (using HO) and a proper reducing condition (proper dose of glucose) with VO powder as the raw material, would be more beneficial for the reversible storage of K when used as the cathode for PIBs compared to other contrast samples. In addition, the enhanced crystallinity and slightly broadened working voltage window of KVO-HG could hinder its long-term cycling stability upon repeated K insertions/extractions.