Synthesis and Electrochemical Performance of V 6 O 13 Nanosheets Film Cathodes for LIBs.

V 6 O 13 thin films were deposited on indium-doped tin oxide (ITO) conductive glass by a concise low-temperature liquid-phase deposition method and through heat treatment. The obtained films were directly used as electrodes without adding any other media. The results indicate that the film annealed at 400 °C exhibited an excellent cycling performance, which remained at 82.7% of capacity after 100 cycles. The film annealed at 400 °C with diffusion coefficients of 6.08 × 10 -12 cm 2 ·s -1 (Li + insertion) and 5.46 × 10 -12 cm 2 ·s -1 (Li + extraction) in the V 6 O 13 film electrode. The high diffusion coefficients could be ascribed to the porous morphology composed of ultrathin nanosheets. Moreover, the film endured phase transitions during electrochemical cycling, the V 6 O 13 partially transformed to Li 0.6 V 1.67 O 3.67 , Li 3 VO 4 , and VO 2 with the insertion of Li + into the lattice, and Li 0.6 V 1.67 O 3.67 , Li 3 VO 4 , and VO 2 partially reversibly transformed backwards to V 6 O 13 with the extraction of Li + from the lattice. The phase transition can be attributed to the unique structure and morphology with enough active sites and ions diffusion channels during cycles. Such findings reveal a bright idea to prepare high-performance cathode materials for LIBs.