Enhancing cycling stability in Li-rich layered oxides by atomic layer deposition of LiNbO3 nanolayers

Abstract

Lithium-rich layered oxides (LROs), serving as high-energy cathode materials for lithium-ion batteries (LIBs), possess significant drawbacks that hinder their widespread use in practical applications. While surface modification can effectively shield LRO from structural degradation, precisely designing the surface structure remains a big challenge. This study focuses on the fabrication of uniform and thickness-controlled LiNbO₃-coated nanostructures on the surface of LRO using the atomic layer deposition (ALD) technique. The LiNbO₃ nanostructures on the cathode surface not only bolster the structural and interfacial stability but also facilitate Li⁺ diffusion, enhancing the cycling stability and the rate capability of LRO. Specifically, the LRO modified with a 3 nm thick LiNbO₃ layer exhibited better capacity retention of 86.4 % after 200 cycles at 1C with a voltage decay rate of 2.86 mV per cycle, and a reversible discharge capacity of 88.1 mAh g⁻¹ at 10C, underscoring the crucial role of surface nanostructures in enhancing electrochemical performance. This research sheds light on the strategic design of nanostructures at the grain surface of advanced cathode materials for high-performance LIBs.