Temperature-Regulated Prelithiated Graphite Anode for an Improved Lithium-Ion Capacitor

A prelithiation method supplies additional lithium ions to compensate for the initial lithium loss to mitigate irreversible capacity loss for lithium-ion capacitors (LICs). With a lower anode potential, LIC enables a broader operational voltage window, a higher energy density, and an extended cycle life. Direct-contact prelithiation (DC-Pr), recognized for its simplicity, practicality, and scalability, has been extensively investigated. However, this method is highly sensitive to operational conditions such as temperature, pressure, and environmental humidity. Here, we propose a temperature-regulated method for the DC-Pr anode and elucidate significant differences in the solid–electrolyte interface (SEI) at different temperatures. This demonstrates that a relatively continuous and uniform SEI forms on the graphite electrode prelithiated at 25 °C, and the composition of the SEI consists of more LiOH, supplemented by LiF and Li 2 CO 3, compared to the compositions prelithiated at 50 and 0 °C. The composite SEI demonstrates improved structural stability, thereby enhancing the Coulombic efficiency and cyclic stability for a lithiated graphite anode. The LIC (AC2||25-Pr-Gr) assembled with an activated carbon cathode (AC2) and lithiated graphite anode (25-Pr-Gr) shows high performance (capacity retention rate of 60.8% for 400 cycles), which is 30% and 10% higher than those of AC2||50-Pr-Gr and AC2||0-Pr-Gr, respectively. This work provides a perspective for the practical application of the DC-Pr method and offers significant guidance for the development of high-performance LICs.