Homogenization and Upcycling of Hetero Spent LiCoO2 Cathodes: Rational Introduction of Li/Co Anti‐Sites Toward Enhanced High‐Voltage Stability

Abstract

AbstractCaptured by relatively low energy consumption and harmful gas‐emission, direct regeneration has captured numerous attention, but still suffers from different particle sizes and diverse doping hetero‐elements, hardly meeting the market demand. Herein, assisted by the crush‐sinter regeneration from element to grain further to particle, homogenized recovery of hetero spent LiCoO2 is successfully carried out. More interestingly, after tailoring Li/Co anti‐sites ratio, the redox activity of Co‐ions is remarkably enhanced, effectively inhibiting the irreversible escape of O‐atoms under high voltage, bringing about the fascinating electrochemical performance and structural stability. As anticipated, the regenerated LiCoO2 delivered a considerable capacity of 175.2 mAh g−1 at 1.0 C, whilst its capacity retention can remain at 88.86% even after 500 cycles at 5.0 C, better than that of commercial materials. Assembling regenerated materials versus. graphite pouch cell, their considerable practical capacity retention can be kept at ≈91.4% even after 500 cycles. Supported by in situ XRD, electronic structure analysis, and detailed DFT calculations, the excellent high voltage stability of optimized samples mainly comes from the alleviating of phase conversion and oxygen redox. This work is expected to shed light on the potential value of homogenized regenerations, and offer effective strategies of upcycling about spent LCO.