Electrochemical Synthesis of Binary Structured Clusters Based on Si Nanoparticles and Si Nanowires for High-Performance Lithium-Ion Battery Anodes

The low electrolysis efficiency of the Si-containing mineral precursor is the main obstacle in fabricating a high-performance Si-based anode via the molten salt electro-deoxygenation strategy. Herein, using commercial SiO as a feedstock, a Si nanoparticle/Si nanowire composited micro-sized Si cluster (p/w-mSi) structure is successfully prepared with the aid of uniformly dispersed Si nanodomains in SiO as a conductive skeleton and the SiO2 matrix in SiO as the precursor of electrolytic Si nanowires. The formation of the Si nanowire in the p/w-mSi cluster is closely related to the three-phase interlines model in the molten salt electrolysis process. The electrolytic p/w-mSi cluster presents a typical void-containing micro-/nano-hierarchical architecture, which can effectively alleviate volume change during the delithiation/lithiation process. As a consequence, p/w-mSi delivers a high specific capacity of 3543.6 mAh g–1 with a high initial Coulombic efficiency of 80.0% at 0.2 A g–1, a high rate capability of 1369 mAh g–1 at 4 A g–1, and excellent cyclability with a satisfactory reversible specific capacity (1078.7 mAh g–1, 400 cycles) at 1 A g–1, far superior to those of SiO and commercial SiNP anodes. More importantly, this study provides an innovative scientific idea for the high-efficiency and short-process construction of silicon-based materials with a micro-/nano-hierarchical architecture.