Expanded graphite incorporated with Li4Ti5O12 nanoparticles as a high-rate lithium-ion battery anode

Abstract

Due to their small interlayer spacing and a low lithiation potential close to Li⁺ deposition, current graphite anodes suffer from weak kinetics, and lithium deposition in a fast-charging process, hindering their practical application in high-power lithium-ion batteries (LIBs). In this work, expanded graphite incorporated with Li₄Ti₅O₁₂ nanoparticles (EG/LTO) was synthesized via moderate oxidization of artificial graphite following a solution coating process. The EG/LTO has sufficient porosity for fast Li⁺ diffusion and a dense Li₄Ti₅O₁₂ layer for decreased interface reaction resistance, resulting in excellent fast-charging properties. EG/LTO presented a high reversible capacity of 272.8 mA h g⁻¹ at 3.74 A g⁻¹ (10C), much higher than that of the original commercial graphite (50.1 mA h g⁻¹ at 10C) and even superior to that of hard carbon. In addition, EG/LTO exhibited capacity retention rate of 98.4% after 500 cycles at 10C, demonstrating high structural stability during a long cycling process. This study provides a protocol for a solution chemistry method to prepare fast-charging graphite anode materials with high stability for high-power LIBs.