Promising Pre-Lithiation Agent Li2C2O4@KB for High-Performance NCM622 Cell

In conventional lithium-ion batteries (LIBs), active lithium loss during solid electrolyte interphase (SEI) formation reduces coulombic efficiency and energy density. Cathode pre-lithiation can effectively compensate for this irreversible lithium consumption. To address limitations of conventional pre-lithiation agents—such as complex synthesis and air instability—a Ketjen black-coated lithium oxalate nanocomposite (Li2C2O4@KB) using high-energy ball milling and spray drying was developed. This composite leverages the advantages of Li2C2O4, including a mild decomposition potential (4.26 V vs. Li+/Li), high theoretical lithium compensation capacity (525 mAh·g−1), and environmentally benign decomposition products, and significantly improves electronic conductivity and reduces particle size. When incorporated in NCM622 full cells, the initial capacity is increased by 18.21 mAh·g−1 at 0.3 C, with a 29.22% enhancement in capacity retention after 50 cycles at 0.3 C. At 1 C, the initial capacity is higher by 15.79 mAh·g−1, accompanied with a 7.72% improvement in retention after 100 cycles. The Li2C2O4@KB composite exhibits great promise as a practical and efficient cathode pre-lithiation additive for next-generation high-energy-density LIBs.