Artificial Organo-Fluoro-Rich Anode Electrolyte Interface and Partially Sodiated Hard Carbon Anode for Improved Cycle Life and Practical Sodium-Ion Batteries

Abstract

In this work, a strategy is introduced wherein without keeping any excess cathode, a practical full-cell sodium-ion battery has been demonstrated by utilizing a hard carbon (hc) anode and sodium vanadium fluorophosphate and carbon nanotube composite (nvpf@c@cnt) cathode. A thin, robust, and durable solid electrolyte interface (sei) is created on the surface of hc through its incubation wetted with a fluoroethylene carbonate (fec)-rich warm electrolyte in direct contact with na metal. During the incubation, the hc anode is partially sodiated and passivated with a thin sei layer. The sodium-ion full cell fabricated while maintaining n/p ∼1.1 showed the first cycle coulombic efficiency of ∼97% and delivered a stable areal capacity of 1.4 mah cm-2at a current rate of 0.1 ma cm-2realized for the first time to the best of our knowledge. The full cell also showed a good rate capability, retaining 1.18 mah cm-2of its initial capacity even at a high current rate of 0.5 ma cm-2, and excellent cycling stability, giving a capacity of ∼1.0 mah cm-2after 500 cycles. The current strategy presents a practical way to make a sodium-ion full cell, utilizing no excess cathode material, significantly saving cost and time. © 2022 american chemical society. All rights reserved.