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

这个小型企业技术转移第一阶段项目将寻求改善锂离子（Li-ion）电池中使用的阴极材料的性能。LiCoO2是主要的正极材料，但它相对昂贵，并且存在安全问题。一种更安全的替代品是LiMn2O4，但它的利用率受到相对较高的褪色能力的限制；即反复循环导致容量下降。该项目将研究陶瓷涂层的纳米孔结构对LiMn2O4褪色能力的影响。研究了不同材料组成和不同烧成温度在LiMn2O4上制备纳米二氧化钛和氧化锆薄膜涂层。将在55℃的温度下对不同的涂层配方进行固定速率循环试验（1C），以确定容量降低到初始值的80%之前的循环次数。性能最好的配方将进一步使用至少200次的高速循环和渐进速率循环进行测试。该配方也将在LiCoO2上进行测试。目标是将涂层阴极材料的寿命与未涂层材料相比提高一个数量级。该项目还有望为纳米颗粒涂层技术提供更多的理解，这些技术可能适用于各种储能应用。如果成功，该项目的广泛/商业影响将导致锂离子电池循环寿命的改善，并允许使用更安全的材料。尽管锂离子电池在消费电子产品中得到了广泛的接受，但在其他市场，特别是运输应用中，其使用寿命和安全问题一直受到限制。提高这些电池中使用的更安全材料的使用寿命可以提高锂离子电池在交通运输和其他大型市场的渗透率，从而进入70亿美元的终端用户市场。该项目的成功结果将影响需要提高循环寿命和热稳定性的应用。

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.