Defect-driven upcycling of degraded LiCoO2 via vacancy-enabled structural reinforcement

Sustainable battery recycling increasingly requires approaches that can restore electrochemical performance rather than simply recover individual elements. In this work, a regeneration strategy is developed for degraded LiCoO 2 (D-LCO) cathodes by utilizing lithium (Li) vacancies formed during long-term cycling as effective sites for structural modification. By taking advantage of these defects in degraded LiCoO 2 , a small amount of lanthanum (La) is incorporated into the layered lattice through a short thermal regeneration process, leading to simultaneous improvements in both structure and kinetics. Expansion of the c -axis spacing stabilizes the layered framework by suppressing Li/Co cation mixing and mitigating irreversible phase transitions during cycling. At the same time, the widened interlayer pathways facilitate Li + transport and reduce charge-transfer resistance. Together, these effects account for the enhanced electrochemical behavior of the regenerated cathode. As a result, the regenerated LiCoO 2 (R-LCO) delivers a reversible capacity of 145.35 mA h g −1 and retains 82.64% of its initial capacity after 500 cycles, exceeding the performance of commercial LiCoO 2 under identical conditions. This study demonstrates a practical route for regenerating layered cathode materials with improved functionality and provides a viable direction for high-value battery recycling. This work achieves direct upcycling of degraded LiCoO 2 cathodes via utilizing lithium (Li) vacancies formed during long-term cycling as effective sites for structural modification and provides a promising pathway for high-value battery recycling. Download: Download high-res image (185KB) Download: Download full-size image