Synthesis of passively prelithiated SiOx nanoparticles for Li-ion battery anode

A new concept of passive prelithiation to SiOx nanoparticles is introduced and evaluated by investigating their nanostructures and electrochemical properties. Specifically, Li is incorporated into SiOx nanoparticles during the nanoparticle synthesis. We obtain Si-Li-O-based nanoparticles, which we call SILIO; these are much larger than SiOx particles and have totally different nanostructures. Due to nanostructures with various phase distributions, SILIO nanoparticles show enhanced electrochemical properties. The initial reversible capacity (IRC) and initial columbic efficiency (ICE) of SILIO nanoparticles are 946 to 1107 mAh/g and 72% to 77%, respectively, while SiOx exhibits 1,064 mAh/g of IRC only with 41.5% of ICE. In addition, the stability of SILIO in the air is evaluated to guarantee no unstable phases such as Li2Ox (x = 0-2) are present in SILIO. Through our findings, we suggest a new nanostructure model composed of crystalline Si, amorphous SiOx, and lithium silicate.