Li3PO4-Coated Graphite Anode for Thermo-Electrochemically Stable Lithium-Ion Batteries

Extensive research on electrode materials has been sparked by the rising demand for high-energy-density rechargeable lithium-ion batteries (LIBs). Graphite is a crucial component of LIB anodes, as more than 90% of the commercialized cathodes are coupled with the graphite anode. For the advanced graphite anode, the fast charge-discharge electrochemical performance and the thermal stability need to be further improved in order to meet the growing demand. Herein, a graphite anode material's thermo-electrochemical stability was improved by the surface coating of lithium phosphate (Li3PO4; LPO). The graphite anode with a well-dispersed LPO-coating layer (graphite@LPO) demonstrated significant improvement in the cycle and rate performances. The graphite@LPO sample showed a capacity retention of 67.8% after 300 cycles at 60 ?, whereas the pristine graphite anode failed after 225 cycles, confirming the ameliorated thermo-electrochemical stability and cyclability by LPO coating. The improved thermo-electrochemical stability of the graphite@LPO anode was validated by the full-cell tests as well. The performance enhancement by LPO-coating is due to the suppression of the growth of the surface film and charge-transfer resistances during the repeated cycling, as evidenced by the electrochemical impedance spectroscopy analysis.

Automated summary

Extensive research has been conducted on electrode materials for rechargeable lithium-ion batteries (LIBs) due to increasing demand. Graphite plays a crucial role as a component of LIB anodes, and improving its charge-discharge performance and thermal stability is essential. This study demonstrates improved thermo-electrochemical stability and cyclability of a graphite anode by coating it with lithium phosphate (Li3PO4; LPO). The LPO-coated graphite anode showed significant enhancements in cycle and rate performances.