Physical vapor deposition of TiO2 nanoparticles on artificial graphite: an excellent anode for high rate and long cycle life lithium-ion batteries

Abstract

Artificial graphite powder (AGP) is one of the utmost common anode materials for lithium-ion batteries (LIB). Nevertheless, the dissolution of the anode material into the electrolyte is one of the main challenges that causes the vanishing capacity and poor cyclability. In this study, a nanoscale TiO2 film is uniformly sputtered on the surface of bare artificial graphite (BAG) electrode through the physical vapor deposition (PVD). The results obviously prove that TiO2 film is completely and homogeneously covered on the BAG electrodes. BAG and AG/TiO2 electrodes represent discharge capacities of 339.3 and 369 mAh g−1 at first cycle, respectively. Therefore, the nano-layer coating of TiO2 increases the initial discharge capacity of artificial graphite around 9%. After 100 cycles, the values of capacity retention at a current density of 0.5 C are 88.7 and 94.2% for BAG and AG/TiO2, respectively. The discharge specific capacity of pouch full cells using BAG and AG/TiO2 anodes versus NCA cathode reveals that AG/TiO2 anodes could still provide a high reversible capacity of around 123.05 mAh g−1 after 10 cycles at a high current density of 4 C. This corresponds to 346.5% improvement compared with BAG anodes versus NCA cathode at 4 C.