PVA-assisted spray deposited porous Li 4 Ti 5 O 12 thin film as high-rate and long-cycle anode for lithium-ion thin-film batteries

Spinel Li Ti O (LTO), a zero-strain material, is a promising anode material for solid-state thin-film lithium-ion batteries (TFB). However, the preparation of high-performance Li Ti O thin-film electrodes through facile methods remains a significant challenge. Herein, we present a novel approach to prepare a binder- and conductor-free porous Li Ti O (P-LTO) thin-film. This approach polyvinyl alcohol (PVA)-assisted spray deposition and does not require the use of complex or expensive methods. Adding PVA to the precursor solution effectively prevents thin-film cracking during high-temperature annealing, enhances adhesion, and forms a highly interconnected porous structure. This unique structure shortens the lithium-ion diffusion pathways and facilitates electron transport. Therefore, P-LTO thin film electrodes demonstrate exceptional rate capacity of 104.1 mAh/g at a current density of 100C. In addition, the electrodes exhibit ultra-long cycle stability, retaining 80.9 % capacity after 10,000 cycles at 10C. This work offers a novel approach for the preparation of high-performance thin-film electrodes for TFBs.