Improving the electrochemical cycling performance of anode materials via facile in situ surface deposition of a solid electrolyte layer

In this paper, we report a facile method for the in situ deposition of a thin solid electrolyte layer on the surface of anode materials, which can significantly improve the rate capability and reduce the time for reaching capacity maximum. The thin solid electrolyte layer (∼8 nm) is formed by adding a small amount of LiNO3 into the anode materials; the added LiNO3 decomposes irreversibly into Li3N and LiNxOy on the surface of the anode materials during the first cycle, facilitating fast diffusion of lithium ions and limiting the formation of the surface electrolyte interface films. This is verified by adding LiNO3 into graphite half-cells which shows a fast activation process at high current density: in particular, the charge capacity reaches its maximum after only ∼30 and ∼40 cycles at 170 and 340 mA g−1, respectively, compared to ∼50 and ∼80 cycles for the graphite half-cell. Furthermore, the LiNO3 additive results in high capacity retention at high C-rates, with a value of 82.4% at 680 mA g−1, compared with 22.4% for the graphite half-cell. The facile and low-cost method reported here is expected to be readily applicable to other electrode materials for high-performance lithium-ion batteries.