A Long-Cycling Aqueous Zinc-Ion Pouch Cell: NASICON-Type Material and Surface Modification

Aqueous zinc-ion batteries (ZIBs) have become the highest potential energy storage system for large-scale applications owing to the high specific capacity, good safety and low cost. In this work, a NASICON-type Na₃ V₂ (PO₄ )₃ cathode modified by a uniform carbon layer (NVP/C) has been synthesized via a facile solid-state method and exhibited significantly improved electrochemical performance when working in an aqueous ZIB. Specifically, the NVP/C cathode shows an excellent rate capacity (e. g., 48 mAh g^-1 at 1.0 A g^-1 ). Good cycle stability is also achieved (e. g., showing a capacity retention of 88% after 2000 cycles at 1.0 A g^-1 ). Furthermore, the Zn²⁺ (de)intercalation mechanism in the NVP cathode has been determined by various ex-situ techniques. In addition, a Zn||NVP/C pouch cell has been assembled, delivering a high capacity of 89 mAhg^-1 at 0.2 A g^-1 and exhibiting a superior long cycling stability.