Synthesis of nanostructured LiMn₂O₄ thin films by glancing angle deposition for Li-ion battery applications

The development of electric vehicles and portable electronic devices demands lighter and thinner batteries with improved specific charge and rate capabilities. In this work, thin films of LiMn₂O₄ were fabricated by rf magnetron sputtering. Glancing angle deposition is introduced as a promising approach for fabrication of porous cathode thin films with 2.6 times the capacity in comparison with conventionally sputtered films of the same thickness. Surface morphology and crystallinity of the films are studied along with their electrochemical performance in an aqueous electrolyte. The glancing angle deposited films can reach a rate capability of up to 4 mA cm^-2 with minimal energy loss, and a life cycle longer than 100 charge/discharge cycles.