Rapid, in situ synthesis of ultra-small silicon particles for boosted lithium storage capability through ultrafast Joule heating

High-capacity anodes, especially silicon, suffer from huge volume fluctuations and electrode material pulverization during lithiation/delithiation. An accessible solution to this issue is to construct nano-silicon anodes with optimized particle size and a conductive matrix. In this work, we introduce a novel strategy for the in situ, rapid synthesis of ultra-small silicon nanoparticles uniformly embedded within carbonized nanosheets (us-Si/C) through swift high-temperature thermal radiative heating of sizable silicon nanoparticles (SiNPs). The us-Si/C anode shows ample capability to accommodate volume fluctuations during the lithiation/delithiation processes. The as-prepared anode exhibits a specific capacity of 920 mA h g^-1 after 1000 cycles at a current density of 2 A g^-1, indicating the advantages of the well-tailored structure. Additionally, the us-Si/C electrode can maintain an areal capacity of approximately 1.55 mA h cm^-2 after 200 cycles at a high loading of 3.66 mg cm^-2. Moreover, it presents practical applicability when assembled into LFP (lithium iron phosphate)//us-Si/C full cells. This preparation method presents great promise for achieving roll-to-roll manufacturing for practical applications due to its simplicity and efficiency.