An On-Line Transient Study on Gassing Mechanism of Lithium Titanate Batteries

Abstract

Gassing at elevated temperature is the main reason for the performance degradation of lithium titanate (Li 4 Ti 5 O 12 , LTO) batteries. In this study, an in-situ device was developed and used to study on-line the transient gassing of custom-made 4.5Ah LTO/NCM pouch batteries at 1C cycling at 55°C. The gas volume and internal pressure of the batteries were recorded on-line for 1000 h, and the composition of the gas components at different times was also analyzed by on-line gas chromatography. The results show that H 2 and CO 2 are the main gas components. The H 2 percentage decreases, while the CO 2 percentage increases gradually during the process of gassing. According to the rate-controlling step of gassing from H 2 formation reaction to CO 2 , a stage-by-stage mixed gassing mechanism is proposed, where the water decomposition is dominant in the initial stage and solvent decomposition is dominant in the subsequent stage. The gassing of LTO batteries aged at 55°C was studied on-line at different states of charge (0%, 50%, 100% SOC). The results show that the volume and composition of the gas are essentially independent of the SOC of batteries and that formation of SEI at LTO interface is the main reason for the gassing rate reduction when aged and cycled (final phase) at 55°C.

Titanium Niobium Oxide: From Discovery to Application in Fast-Charging Lithium-Ion Batteries

“…In all electrode materials, the increased particle surface area inherent to nanomaterials must be balanced against other performance factors such as electrode–electrolyte reactivity and cycle life as well as external factors such as cost and scalability (section 4.1). Gas generation from Li 4 Ti 5 O 12 with standard electrolytes and residual moisture is well-known , and has now also been found in TiNb 2 O 7 -based batteries. Buannic et al found that TiNb 2 O 7 gassing under reasonable but relatively harsh conditions ((i) cycling against a high voltage LiNi 0.5 Mn 1.5 O 4 cathode or (ii) storage at 45 °C against a LiNi 1/3 Mn 1/3 Co 1/3 O 2 cathode) was equivalent to, or worse than, Li 4 Ti 5 O 12 and was a function of TiNb 2 O 7 surface area with 32 m 2 g –1 particles evolving more gas than 6 m 2 g –1 particles annealed at a higher temperature .…”

Clarification on the Gassing Behavior of Carbon‐Coated Li4Ti5O12 at Elevated Temperature: Importance of Coating Coverage

“…However, gassing is one of the serious issues in batteries at elevated temperatures. Over the years, there have been many publications on the gassing behavior of LTO based LIBs, which shows the keen importance of LTO electrodes on EV application [8–13] . LTO based LIBs gassing is much more severe, which limits the usage of LTO, despite its advantage for EV applications.…”

“…Over the years, there have been many publications on the gassing behavior of LTO based LIBs, which shows the keen importance of LTO electrodes on EV application. [8][9][10][11][12][13] LTO based LIBs gassing is much more severe, which limits the usage of LTO, despite its advantage for EV applications. In graphite-based LIBs, electrolyte decomposes during the initial cycle and forms a stable solid electrolyte interphase (SEI) layer.…”