Rod shape Li4Ti5O12 additives for enhanced cycle performance of silicon-graphite anode in lithium-ion batteries at elevated temperature

Abstract

The severe resistance increases in the Si-based anode caused by the low Li-ion and electrical conductivity associated with significant volume change of Si during lithiation/delithiation process deteriorate the electrochemical performances in lithium-ion batteries (LIBs) at elevated temperature. Here, we report a simple and effective strategy to alleviate the degradation of Li-ion and electrical conductivity during cycling by introducing the rod shape Li4Ti5O12 (LTO) in the Si-graphite anode (SGA). The LTO rod on the surface of the SGA facilitates the formation of dense inorganic solid-electrolyte interphase (SEI) layer, which suppresses thickening behavior of SEI layer resulting in enhanced Li-ion conductivity. Moreover, the LTO rod existing in a lithiated form in the SGA during full-cell operation acts as electrical conducting paths between active materials, which improves electrical conductivity. The SGA employing LTO rod exhibits reduced resistances of SEI layer and charge transfer after formation and 100th cycles, and improved cycling stability compared to those of the pristine SGA.