In-situ growth of MoO2@N doped carbon on Mo2C-MXene for superior lithium storage

Molybdenum dioxide (MoO2) with high theoretical capacity and low cost has triggered extensive interest as a renowned anode for lithium ion batteries (LIBs). However, the sluggish diffusion kinetics and severe capacity decay obstructed its practical application. Herein, hierarchical spherical Mo2[email protected]2@C was fabricated through a self-assembly and carbonization strategy. DFT calculations and experimental results revealed that the incorporation of metallic Mo2C-MXene and carbon into MoO2 not only modulated the charge distribution and weakened Mo-O bond of MoO2, but also promoted the adsorption of Li+ on MoO2 and lowered the migration energy barrier for Li+, thereby accelerating the electrochemical kinetics, inducing a strong diffusion-controlled charge storage behavior and improving the electrochemical reversibility. In addition, the introduction of MXene reinforced the structural integrity of MoO2 during ion insertion and extraction, which ameliorated the electrochemical stability. Beneficiating from the above synergistic effect, the optimized Mo2[email protected]2@C delivered remarkable cycling capacity (854.5 mAh g−1 after 500 cycles at 0.5 A g−1) and superior rate capacity (644.4 mAh g−1 at 1 A g−1) for lithium storage. This work disclosed the charge storage mechanism of MoO2 and provided new guidance for the rational design of novel electrode materials for secondary batteries.