Effect of Amorphous LiPON Coating on Electrochemical Performance of LiNi <sub>0.8</sub> Mn <sub>0.1</sub> Co <sub>0.1</sub> O <sub>2</sub> (NMC811) in All Solid-State Batteries
Sushovan Shrestha, Jongbeon Kim, Jejun Jeong, Hye Jin Lee, Seul Cham Kim, Hoe Jin Hah, Kyu‐Hwan Oh, Se-Hee Lee
Abstract
High nickel layered oxide LiNi 0.8 Mn 0.1 Co 0.1 O 2 (NMC811) was coated with a nanometer layer coating of a lithium ion conducting solid electrolyte, lithium phosphorus oxynitride (LiPON) by using RF-magnetron sputtering. The cells with LiPON coated NMC811 exhibit much improved cycling performance compared to the cells with pristine NMC811 with 64.1% and 42.6% capacity retention respectively over 100 cycles in an all solid-state battery. The LiPON layer provides interfacial stability at high voltages, suppresses the growth of impedance with cycling and improves the rate capability. Thicker coatings show a negative impact on the performance owing to the increase in electronic resistance with increasing thickness of the LiPON layer. The dQ/dV analysis, electrochemical impedance spectroscopy (EIS), and the overpotential study during galvanostatic cycling were conducted to elucidate the improvement of the cycling stability and enhancement of Li + transport through LiPON layers surrounding NMC811.