Enhanced electrochemical performance of silicon anode materials with titanium hydride treatment

As a promising anode material for the next generation of lithium-ion batteries, silicon (Si) suffers from the main problems of severe volume expansion and poor electrical conductivity. Compounding Si-based materials with metal hydrides is one of the ways to overcome these problems. Herein, we proposed TiH2 decorated Si com-posites prepared by ball milling and subsequent high-temperature calcination to restrain the volume expansion of Si and enhance the electrical conductivity. The resulting Si-0.05TiH2 anode delivered a reversible discharge capacity of 766.1 mAh/g after 100 cycles at a current density of 100 mA/g and better rate capability than the Si anode. Additionally, the impedance measurements and the density functional theory (DFT) calculation demon-strated that the insertion of Ti after dehydrogenation of TiH2 enhanced the conductivity of the composite anode. The charge transfer resistance (Rct) of Si-0.05TiH2 and Si anodes were 43.03 omega and 609.6 omega, respec-tively, indicated that the charge transfer process of Si/TiH2 electrodes was faster. This study provides a new strategy for compounding metal hydrides with Si, and a further attempt to enhance the electrochemical prop-erties of Si.