LiCl surface engineering for stable and kinetically enhanced hard carbon anodes in lithium-ion batteries

초록

Hard carbon (HC) gains attention as a potential alternative anode material in Na-ion and Li-ion battery systems. However, the practical implementation of HC anodes is limited by interfacial instability and irreversible Li accumulation in the low-potential plateau region. In this study, we develop a surface engineering strategy using LiCl coating to stabilize the electrode-electrolyte interface in HC electrodes and promote reversible Li+ transport within the electrodes. The optimized 5-wt% LiCl/HC electrode demonstrates a reduced activation energy for Li+ migration and an enhanced diffusion coefficient, as confirmed by temperature-dependent electrochemical impedance spectroscopy and Randles-Sevcik analysis. The galvanostatic intermittent titration technique reveals suppressed polarization and improved Li+ kinetics during pore-to-graphitic transitions. Under overlithiation conditions (500 mAh g(-1)), the 5-wt% LiCl/HC electrode maintains a stable plateau and a sloping profile with a lower nucleation barrier and higher Coulombic efficiency >95.5%) over 200 cycles compared with the bare HC electrode. Post-cycling analyses confirms uniform Li deposition, suppressed dendrite growth, and reduced solid electrolyte interphase thickening in the 5-wt% LiCl/HC electrode. This study demonstrates an effective and scalable interfacial engineering strategy of LiCl surface modification on HC electrodes that can improve the durability and performance of HC anodes in next-generation LIBs.

키워드