Nanocrystalline mesoporous LiFePO4 thin-films as cathodes for Li-ion microbatteries

Abstract

Mesoporous LiFePO₄ thin films prepared using a facile and low-cost synthesis approach have been studied as electrodes for Li-ion batteries. LiFePO₄ mesoporous films (∼300 nm) were synthesized by a template-directed sol–gel chemistry coupled with the dip-coating approach, followed by heat-treatment under a reducing atmosphere (10% H₂/N₂) at temperatures ranging from 400 to 760 °C. These mesostructured LiFePO₄ films are constituted of a connected network of mesopores (∼60 nm) and an assembly of crystalline nanoparticles (∼50 nm) in the pore wall. In addition, the presence of carbon, evidenced by Raman spectroscopy, provides efficient electron pathways along the 3-D nanoarchitectures. Cycling performance was evaluated for optimal nanocrystalline LiFePO₄ thin films showing an excellent high rate performance after 1000 cycles (158 mA h g⁻¹). These data provide important information on new types of porous architectures for the design of efficient electrodes for micro-batteries.