《Hierarchical spherical Mo2C/N-doped graphene catalyst facilitates low-voltage Li2C2O4 prelithiation》

Self-sacrificing Li2C2O4 is considered to be a very promising lithium supplementation agent due to its high specific capacity, low cost and residue-free properties. However, the inherently low electrochemical activity results in a decomposition potential of up to 4.7V, which is not conducive to its compatibility with existing electrolytes and cathode materials. Here, we synthesized a three-dimensional graded spherical Mo2C/N-doped graphene catalyst using a self-polymerization and high-temperature annealing strategy. The synergistic catalytic effect of Mo2C and N-doped graphene enhanced the reactivity of Li2C2O4. A hierarchical three-dimensional conductive network accelerates the conduction of electrons and ions. The freeze-drying composite technology ensures that the nano-Li2C2O4 is evenly wrapped inside the spherical catalyst. Thanks to the above advantages, the decomposition potential of Li2C2O4 is reduced from 4.7V to 4.16V. Eventually, under the action of the compound lithium supplement, Gr||LFP and SiC ||The capacity of the LFP battery has been increased by 15% and 22%, respectively. In addition, the ex situ XPS and energy spectroscopy show that the stability of SEI is enhanced after pre-lithiation, which in turn ensures excellent cycling performance.

https://doi.org/10.1016/j.nanoen.2023.108757