Toward High Power Batteries: Pre-lithiated Carbon Nanospheres as High Rate Anode Material for Lithium Ion Batteries

In this work, carbon nanospheres (CS) are prepared by hydrothermal synthesis using glucose as precursor, followed by a subsequent carbonization step. By variation of the synthesis parameters, CS particles with different particle sizes are obtained. With particular focus on the fast charging capability, the electrochemical performance of CS as anode material in lithium ion batteries (LIBs) is investigated, including the influence of particle size and carbonization temperature. It is shown that CS possess an extraordinary good long-term cycling stability and a very good rate capability (up to 20C charge/discharge rate) at operating temperatures of 20 and 0 °C compared to graphitic carbon and Li4Ti5O12 (LTO)-based anodes. One major disadvantage of CS is the very low first cycle Coulombic efficiency (Ceff) and the related high active lithium loss, which prevents usage of CS within LIB full cells. Nevertheless, in order to overcome this problem, we performed electrochemical pre-lithiation, which significantly improves the first cycle Ceff and enables usage of CS within LIB full cells (vs NMC-111), which is shown here for the first time. The improved rate capability of CS is also verified in electrochemically pre-lithiated NMC-based LIB full cells, in comparison to graphite and LTO anodes. Further, CS also display an improved specific energy (at ≥5C), energy efficiency (at ≥2C), and energy retention (at ≥2C) compared to graphite and LTO-based LIB full cells.