Remarkably Improved Cycling Stability Of Boron-Strengthened Multicomponent Layer Protected Micron-Si Composite Anode

The development of micron-sized Si as an in alleviating its vast volume expansion during lithiation. Herein, we successfully prepare a spherical Si composite coated by a boron-strengthened multicomponent surface layer, via heating of Si particles with LiBH4 followed by a mechanochemical reaction with CO,. The thin high-strength outer layer consists of amorphous SiOx/C, in which ultrafine nanocrystals of SiC and Li2SiO3 and amorphous B and B2O3 species, are well-dispersed. These multicomponent nanocrystals and B species reinforce effectively the mechanical properties of the amorphous SiOx/C conformal layer, which restrains greatly the volume expansion in the lithiation process and stabilizes the forming solid electrolyte interphase layer due to the reduced cracks and pulverization of the anode material and consequently leads to a remarkable long-term cyclability. An initial capacity of 1385 mAh g(-1) at 100 mA g(-1) is measured with a good cycling stability, which still retained 70.5% of the capacity over 600 deep cycles.