STTR Phase I: Using Nanoparticle Oxide Coatings to Increase Cycle Life of Cathode Materials for Li-Ion Batteries

This Small Business Technology Transfer Phase I project will seek to improve the performance of the cathode materials used in lithium-ion (Li-ion) batteries. LiCoO2 is the primary cathode material, but it is relatively expensive, and has safety concerns. A safer alternative is LiMn2O4, but its utilization is limited by a relatively higher fade capacity; i.e. decrease in capacity with repeated cycling. The project will investigate the effects of nanoporous structure of ceramic coatings on the fade capacity of LiMn2O4. Different material composition and firing temperatures of thin-film coatings of titania and zirconia nanoparticles on LiMn2O4 will be studied. Fixed rate cycle tests (1C) will be performed at a temperature of 55C for different coating formulations to determine the number of cycles before the capacity decreases to 80% of the initial value. The best performing formulation will be tested further using both high-rate cycling for at least 200 cycles and progressive rate cycling. This formulation will also be tested on LiCoO2. The goal is to increase the life of the coated cathode material by an order of magnitude as compared to the uncoated material. This project is also expected to provide additional understanding of nanoparticle coating techniques that may be applicable to variety of energy storage applications. The broader/commercial impact of this project, if successful, will result in improvements in the cycle life of Li-ion batteries and allow the use of safer materials. Although lithium-ion batteries have gained wide acceptance in consumer electronic products, their use in other markets, particularly transportation applications, has been limited by their lifetimes and safety concerns. Improving the lifetime of the safer materials used in these batteries can enhance Li-ion batteries' penetration into transportation and other large markets, enabling access to a $7 billion end user market. The successful outcome of this project will impact applications where there is a need for enhanced cycle life and thermal stability.