In Situ Constructed Spinel Layer Stabilized Upcycled LiCoO 2 for High Performance Lithium-Ion Batteries.

With ever-increasing requirements for cathodes in the lithium-ion batteries market, an efficiency and eco-friendly upcycling regeneration strategy is imperative to meet the demand for high-performance cathode materials. Herein, a facile, direct and upcycling regeneration strategy is proposed to restore the failed LiCoO 2 and enhance the stability at 4.6 V. Double effects combination of relithiation and outside surface reconstruction are simultaneously achieved via a facile solid-phase sintering method. The evolution process of the Li-supplement and grain-recrystallization is systematically investigated, and the high performance of the upcycled materials at high voltage is comprehensively demonstrated. Thanks to the favorable spinel LiCo x Mn 2-x O 4 surface coating, the upcycled sample displays outstanding electrochemical performance, superior to the pristine cathode materials. Notably, the 1% surface-coated LiCoO 2 achieves a high discharge-specific capacity of 207.9 mA h g -1 at 0.1 C and delivers excellent cyclability with 77.0% capacity retention after 300 cycles. Significantly, this in situ created spinel coating layer can be potentially utilized for recycling spent LiCoO 2 , thus providing a viable, promising recycling strategy insights into the upcycling of degraded cathodes.