Interfacial pre-activation of lithium oxalate via d-p hybridization in intermetallic NiBi3 for cathode prelithiation

Lithium oxalate (Li 2 C 2 O 4 ) is regarded as a promising prelithiation agent due to its high specific capacity and cost-effectiveness. However, its intrinsically poor electronic conductivity and sluggish reaction kinetics result in a high lithium liberation potential (typically above 4.5 V), which challenges the stability of electrolytes and electrode materials, and deteriorates overall battery performance. In this work, the intermetallic NiBi 3 catalyst with metallic conductivity and strong interfacial interaction is introduced to promote the low-potential decomposition of Li 2 C 2 O 4 . Benefiting from the synergistic electronic effect between Ni and Bi, the incorporation of Bi effectively modulates the electronic structure of Ni sites via d – p orbital hybridization, thereby enhancing the adsorption and activation of Li 2 C 2 O 4 , weakening the Li 2 C 2 O 4 framework and facilitating its decomposition. When coupled with ultrahigh-Ni NCM96 cathodes, the NiBi 3 -Li 2 C 2 O 4 prelithiation system provides higher charge capacity (273.3 mAh g −1 ) and improved reaction kinetics compared to the pristine counterpart. Furthermore, full-cell configurations based on SiO x anodes exhibit enhanced lithium compensation capability, maintaining a capacity retention of 52.9% after 150 cycles at 0.5C. These results demonstrate that intermetallic NiBi 3 is an efficient catalyst for activating Li 2 C 2 O 4 and provides a viable strategy for developing high-performance cathode prelithiation systems. Download: Download high-res image (119KB) Download: Download full-size image