Implementation and characterization of silicon anode with metal alloy inactive matrix for lithium-ion secondary batteries

Searching for new electrode materials with high capacity and energy density for use in Li-ion batteries is currently an important research topic. However, there is an urgent demand for more compact batteries for large-scale applications. We fabricated Si-Ti-Ni (STN) alloys by melt spinning and analyzed their crystal structure by X-ray diffraction and transmission electron and scanning electron microscopy. During Li insertion into the alloy electrodes, Si crystallites (active material) reacted with Li to form Li_xSi alloys. The STN phase was the inactive matrix. To improve the electrochemical performance (initial efficiency, cycle life, etc.), the structure and composition of the STN anode were optimized. With 65 at% Si, the initial efficiency dramatically improved to 76%, and after 100 cycles, the charge/discharge efficiency was very high, 80%. In terms of cycle performance, the carbon coating and the electrolyte matching will be expected to reach the graphite level.