Raj Das Gupta

Abstract:

Lithium ion batteries have become critical energy storage devices, not only for the plethora of consumer electronics that we depend on daily, but also for electric vehicles and utility energy storage systems that will be essential for combating climate change and enabling clean energy. Consequently, substantial investments have been made in both manufacturing capacity and research programs globally. However, the manufacturing processes used to produce lithium ion batteries are neither inexpensive nor environmentally benign. Current manufacturing processes employ a solvent based slurry mixing/coating method with N-Methyl-2-pyrrolidone (NMP) as the solvent of choice. NMP has recently been identified as a known reproductive toxicant, and as a result, its use is increasingly restricted in the E.U, North America and Japan. In addition to escalating the potential liability and environmental repercussions for its use, the use of NMP is partially responsible for the high of the costs of lithium ion batteries, where it can be responsible for over 50% of the processing costs. NMP-free production processes would not only offer a truly 'green' lithium ion battery, but they would also enable a breakthrough in cost reductions which could have massive beneficial global consequences. Recently, Electrovaya launched its second generation coating technology that avoids the use of NMP altogether, while also enhancing the quality of the electrode coating. A comparison of the microstructure and performance of electrodes produced with Electrovaya's process and conventional NMP methods is shown. This includes both SEM/TEM analysis in addition to novel TOF-SIMS analysis methods. Finally, the new process also allows the use of sensitive additives, which will further enhance the performance and energy density of lithium ion batteries.