Abstract： This study investigates the capacity degradation mechanism of 18650-type high-nickel/silicon- carbon lithium-ion batteries by analyzing the charge and discharge capacities, average charge and discharge voltages, and differential voltage, combined with the characterization of morphology, structure, and composition of the battery’s internal components. Results show that during lithiation/delithiation, the anode causes a cumulative capacity loss of 1 300.5 mAh. In contrast, the positive electrode contributes a cumulative capacity of 332.5 mAh from the differential lithium ions, as its lithium ions delithiation continuously exceeds lithiation. Along with the loss of active lithium ions, the structural stability of the cathode active material NCM811 gradually deteriorated, ultimately leading to the fragmentation of secondary particles. Under the confinement of the rigid battery casing, the fragmented and detached particles maintained electrical contact with the current collector and could still function in lithium storage. However, particle fragmentation might accelerate electrolyte consumption, resulting in a significant increase in battery internal resistance in the late cycling stage. The findings of this study indicate that the key mechanism of capacity fading in this type of battery is dominated by negative electrode capacity loss, with electrolyte consumption synergistically exacerbating the fading. Additionally, the proposed rapid analysis method for lithium-ion battery capacity fading provides support for cell design, rapid material screening, and battery performance optimization.
DENG Jie,ZHANG Siyu,JIANG Jianzhong. Investigation of Nickel-Rich/Silicon-Graphite Lithium-Ion Battery Degradation Mechanisms by Charge-Discharge Cycle Evaluation[J]. Chemical Reaction Engineering and Technology, 2026, 42(1): 53-64.
