Unlocking the decomposition limitations of the Li2C2O4 for highly efficient cathode preliathiations

Abstract

The development of high-energy-density Li-ion batteries is hindered by the irreversible capacity loss during the initial charge-discharge process. Therefore, pre-lithiation technology has emerged in the past few decades as a powerful method to supplement the undesired lithium loss, thereby maximizing the energy utilization of LIBs and extending their cycle life. Lithium oxalate (Li₂C₂O₄), with a high lithium content and excellent air stability, has been considered one of the most promising materials for lithium compensation. However, the sluggish electrochemical decomposition kinetics of the material severely hinders its further commercial application. Here, we introduce a recrystallization strategy combined with atomic Ni catalysts to modulate the mass transport and decomposition reaction kinetics. The decomposition potential of Li₂C₂O₄ is significantly decreased from ∼4.90V to ∼4.30V with a high compatibility with the current battery systems. In compared to the bare NCM//Li cell, the Ni/N-rGO and Li₂C₂O₄ composite (Ni-LCO) modified cell releases an extra capacity of ∼11.7 ​%. Moreover, this ratio can be magnified in the NCM//SiO_x full cell, resulting in a 30.4 ​% higher reversible capacity. Overall, this work brings the catalytic paradigm into the pre-lithiation technology, which opens another window for the development of high-energy-density battery systems.