High Energy/Capacity Cathode Materials
Funded by U.S. Department of Defense
Project Summary
This SBIR Phase I project was to develop and demonstrate a new class of cathode materials based on nanostructured layered-spinel lithium (Li)-rich manganese nickel oxide Lix(Mn0.75Ni0.25)Oy (0.5 < x < 2, y = 0.5x + 1.75), or LS-LMNO, with a focus on the development of LS-LMNO nanomaterial. This class of materials is expected to offer better performance over currently used cathode materials (e.g. LiCoO2 and LiFePO4), including higher capacity, higher energy, better stability and safety, thereby making the material attractive for use in Li-ion cells for applications in both military systems (such as ground/sea vehicles, aircrafts, and other weapon platforms) and commercial systems (such as portable electronics and hybrid electric vehicles).
The research conducted in Phase I has well demonstrated the technical feasibility of the proposed cathode nanomaterial through material design, synthesis, optimization, and characterization. The key technical issues related to the material processing have been well addressed, and preliminary optimization on material composition, processing parameters have been conducted with an aim of achieving improved performance. Characterization on both microstructure and electrochemical properties of the resultant material has been well conducted. Microstructure analysis indicated the formation of nanoscale LS-LMNO particles. Electrochemical test results showed that very promising performance had been successfully achieved, including extremely high capacity (~279mAh/g at 0.05C), and excellent rate performance (~252mAh/g at 0.1C and ~180 mAh/g at 1C) and cyclability (nearly none capacity degradation after 40 cycles). These results have exceeded the targeted performance of capacity (namely 250 mAh/g at 0.05C or 0.1C), and are better or among the best results as reported in the latest literature. It may also note that in contrast with complex and expensive processes reported in the literature, the cathode material having been investigated can be produced through a cost-effective, scalable process.
In the end of this Phase I project, our research has led to the feasibility demonstration of a novel class of cathode materials based on LS-LMNO nanomaterials, with very promising electrochemical properties. In addition, Phase I research has set forth the direction for future material optimization, including refinement on both composition and processing in order to achieve better performance. Consequently, the investigative study carried out in Phase I has established a solid technical basis for Phase II of this project, which will focus on further performance improvement, process optimization, scale up, and battery cell demonstration/testing.