Innovative Fast‐Charging Protocol Incorporating Proactive Lithium‐Plating Suppression Pulses for Lithium‐Ion Batteries: Protocol Design, Validation, and Post‐Mortem Analysis
Ye Ji Ha, Somi Roh, Bo Keun Park, Minsoo Kim, Dong Ho Jeong, Hyunjae Kim, Inwoo Kim, Yong Nam Jo, Jang Wook Choi, Ki Jae Kim
Abstract
Abstract Conventional fast‐charging using a high constant current can ultimately accelerate uncontrolled Li plating on the graphite anode, resulting in degradation and poor cycle life of Li‐ion batteries (LIBs). Therefore, identifying suitable fast‐charging methods for LIBs is beneficial for the widespread use of electric vehicles (EVs). Herein, an innovative fast‐charging protocol, designed by combining an active control pulse (ACP) with a multi‐step fast‐charging method (M‐ACP), is proposed to mitigate issues related to Li plating and byproduct formation on the graphite anode during fast‐charging. Because M‐ACP not only reduces charging time but also actively prevents Li plating on the graphite anode surface, the 60 Ah pouch cell used in EVs that employ the M‐ACP protocol exhibits an extended lifetime with no capacity fading over 2000 cycles. The degradation behavior of the negative electrodes, which is strongly correlated to the improved performance of M‐ACP cells, is demonstrated using non‐destructive diagnostic techniques and post‐mortem analyses. The M‐ACP cell exhibits significantly less active material and Li loss, and decreased solid electrolyte interphase layer growth on graphite, owing to effective mitigation of Li + accumulation at the electrode/electrolyte interface. Consequently, the distinguished fast‐charging protocol effectively decelerates the degradation of the negative electrode, leading to outstanding electrochemical performance.