Synthesis and electrochemical performance of a nanocrystalline Li4Ti5O12/C composite for lithium-ion batteries prepared using resorcinol–formaldehyde resins

Abstract

Recently, spinel lithium titanate (Li4Ti5O12, LTO) has attracted attention as an anode material for lithium-ion batteries (LIBs). However, the poor electronic conductivity and low lithium-ion diffusion coefficient of LTO suppresses its electrochemical performance during quick charging. One possible way to improve the electrochemical performance is to reduce the LTO particle size to the nanometer range and modify the surface conductivity. In this study, LTO/C was synthesized by a one-step carbonization route without any specialized equipment using a resorcinol–formaldehyde (RF) resin as a carbon source, lithium acetate as a lithium source and polymerization catalyst, and commercial nano-sized TiO2 as a titanium source. The homogeneous mixing of the RF resin dissolved in water led to the uniform dispersion of the TiO2 and the Li source. The polymerization of the RF resin, TiO2, and dissolved Li source formed a closely structured matrix. LTO/C is comprised of crystalline LTO covered by a thin carbon layer. The RF resin plays an essential role in producing a suitable reaction field, preventing grain growth, and controlling the LTO primary particle size. The specific capacities of the LTO/C composite (carbon 15 wt%, carbonized at 900 °C) are 161 and 90 mAh/g at 0.1C and 25C, respectively. The composite shows improved electrochemical properties compared to commercial LTO.