Sn, S co-doped LiCoO2 with low lithium ion diffusion energy barrier and high passivation surface for fast charging lithium ion batteries

High-voltage lithium cobalt oxide (LCO) has been widely used in 5G smart electronics. However, maintaining the stability of high-voltage LCO structures under fast charging and discharging conditions is still a challenge that hinders its application in fast-charging lithium-ion batteries. Here, we propose a new idea of fully supported lattice network and self-passivating surface to construct a fast-charging cathode and realize high performance fast-charging lithium-ion battery. A fully supported lattice network can be achieved by one-step solid-phase sintering of Sn and S co-doped LCO, reducing the energy barrier of Li+ transport and allowing rapid Li+ solidstate diffusion. The self-passivating surface is formed on the surface of LCO-Sn0.6 by de-solvation with solvent molecules, which significantly increases the adsorption energy of EC and LiPF6 on LCO-Sn0.6, and greatly reduces the absorption ability of EC and LiPF6 on LCO-Sn0.6 to form effective CEI membranes. The superior performance with high capacity (114 mAh g+1) under extremely fast charging conditions (20 C, 1 C = 274 mA g+1) is achieved on Sn and S co-doped LCO cathode, that is, it can reach more than 60% SOC after only 2 min of fast charging. In situ Raman spectroscopy and in situ XRD further confirm the reversible transformation of Sn and S co-doped LCO microstructure during charge and discharge processes. These results provide a platform for the design of novel fast-charging cathode materials with fully supported lattice network and self-passivating surface, while stabilizing lattice structure and significantly enhancing ionic solid-state diffusion dynamics.

Automated summary

This study proposes a new method to construct a high-performance cathode for fast-charging lithium-ion batteries, by utilizing a fully supported lattice network and a self-passivating surface. By one-step solid-phase sintering of Sn and S co-doped LCO, a fully supported lattice network is formed, reducing the energy barrier of Li+ transport and promoting Li+ solid-state diffusion. In addition, the self-passivating surface formed on LCO-Sn0.6 significantly enhances the adsorption energy of EC and LiPF6, forming effective CEI membranes and enabling high capacity and SOC after extremely fast charging.