Lithium Transport in an Amorphous Li_xSi Anode Investigated by Quasi-elastic Neutron Scattering

We demonstrate the room temperature mechanochemical synthesis of highly defective Li_xSi anode materials and characterization of the Li transport. We probed the Li⁺ self-diffusion using quasi-elastic neutron scattering (QENS) to measure the Li self-diffusion in the alloy. Li diffusion was found to be significantly greater (3.0 × 10^-6 cm² s^-1) than previously measured crystalline and electrochemically made Li-Si alloys; the energy of activation was determined to be 0.20 eV (19 kJ mol^-1). Amorphous Li-Si structures are known to have superior Li diffusion to their crystalline counterparts; therefore, the isolation and stabilization of defective Li-Si structures may improve the utility of Si anodes for Li-ion batteries.