"Dry-air-stable lithium silicide–lithium oxide core–shell nanoparticles as high-capacity prelithiation reagents"

Jie Zhao: Zhenda Lu, Nian Liu, Hyun-Wook Lee, Matthew T. McDowell & Yi Cui; Nature Communications, 10/03/14.

Additional Authors: Zhenda Lu, Nian Liu, Hyun-Wook Lee, Matthew T. McDowell & Yi Cui

Abstract:

Rapid progress has been made in realizing battery electrode materials with high capacity and long-term cyclability in the past decade. However, low first-cycle Coulombic efficiency as a result of the formation of a solid electrolyte interphase and Li trapping at the anodes, remains unresolved. Here we report LixSi–Li2O core–shell nanoparticles as an excellent prelithiation reagent with high specific capacity to compensate the first-cycle capacity loss. These nanoparticles are produced via a one-step thermal alloying process. LixSi–Li2O core–shell nanoparticles are processible in a slurry and exhibit high capacity under dry-air conditions with the protection of a ​Li2O passivation shell, indicating that these nanoparticles are potentially compatible with industrial battery fabrication processes. Both ​Si and graphite anodes are successfully prelithiated with these nanoparticles to achieve high first-cycle Coulombic efficiencies of 94% to >100%. The LixSi–Li2O core–shell nanoparticles enable the practical implementation of high-performance electrode materials in lithium-ion batteries.