Silicon-based materials have been considered potential anode materials for next-generation lithium-ion batteries based on their high theoretical capacity and low working voltage. However, side reactions at the Si/electrolyte interface bring annoying issues like low Coulombic efficiency, sluggish ionic transport, and inferior temperature compatibility. In this work, the surface Al2 O3 coating layer is proposed as an artificial solid electrolyte interphase (SEI), which can serve as a physical barrier against the invasion of byproducts like HF(Hydrogen Fluoride) from the decomposition of electrolyte, and acts as a fast Li-ion transport pathway. Besides, the intrinsically high mechanical strength can effectively inhibit the volume expansion of the silicon particles, thus promoting the cyclability. The as-assembled battery cell with the Al2 O3 -coated Si-C anode exhibits a high initial Coulombic efficiency of 80% at RT and a capacity retention ratio up to ≈81.9% after 100 cycles, which is much higher than that of the pristine Si-C anode (≈74.8%). Besides, the expansion rate can also be decreased from 103% to 50%. Moreover, the Al2 O3 -coated Si-C anode also extends the working temperature from room temperature to 0 °C-60 °C. Overall, this work provides an efficient strategy for regulating the interface reactions of Si-based anode and pushes forward the practical applications at real conditions.
Keywords: interface engineering; lithium-ion batteries; silicon; wide-temperature applications.
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