Investigation of the Gas Generation in Lithium Titanate Anode Based Lithium Ion Batteries

Abstract

Lithium titanate (LTO), Li 4 Ti 5 O 12 is a promising material for energy storage due to its high-rate capabilities and safety. However, gas generation, which can be observed under high-temperature operation, present a challenge to the large-scale application of lithium ion batteries made from LTO anodes. Here we analyzed sources of gas generation in an LTO system through isotopic tagging of primary suspected sources of H 2. Specifically, we added small amounts of heavy water (D 2 O) to the electrolyte, D 2 O to the LTO electrode, or deuterated dimethyl carbonate (DMC) to the electrolyte. Upon cycling, the isotopic tagging method enables the separation of deuterated from non-deuterated gas products using combined gas chromatography and mass spectroscopy (GC/MS) analysis. The results demonstrate that cell performance and generation of H 2 are both strongly related to moisture content within the cells. Cells with deuterated DMC in the electrolyte show negligible breakdown as determined by the lack of H-D/D 2 gas production when compared to samples that contain D 2 O added into the electrode or electrolyte. These results indicate that the primary source of gas generation in LTO-based cells is residual moisture in the electrodes and electrolyte, reinforcing the importance of low-moisture processing conditions for LTO-based lithium ion batteries.