Suppressing gas evolution in Li4Ti5O12 -based pouch cells by high temperature formation

• Published in: Journal of power sources Vol. 575; p. 233207
• Main Authors: Alsheimer, Lennart, Heidrich, Bastian, Peschel, Christoph, Dienwiebel, Iris, Winter, Martin, Börner, Markus
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.08.2023
• Subjects: Capacity increase; Gassing behavior; High temperature formation; Lithium ion-batteries; LTO; Lithium ion-batteries; Gassing behavior; LTO; High temperature formation; Capacity increase
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2023.233207

Batteries based on Li4Ti5O12 as negative active material, suffer from intense gas evolution during calendaric and cyclic aging, which notably limits their scope of application. In this study, gas evolution in multilayered Li4Ti5O12-based lithium-ion battery pouch cells was investigated during formation at different temperatures and upon subsequent cyclic aging. The results demonstrated that higher temperatures during formation procedure supported the formation of a stable protective decomposition layer on the Li4Ti5O12 composite electrode surface, which successfully prevented gas evolution during charge/discharge cycling without compromising the rate capability of Li4Ti5O12-based lithium-ion batteries. Cell formation at 20 °C and 40 °C showed a continuous increase in cell capacity during subsequent cyclic aging at 40 °C. However, cell formation at 60 °C led to a higher initial capacity without capacity increase during 40 °C cyclic aging. The results showed that this capacity increase is accompanied by gas evolution. To explain this behavior a model is proposed in which gas evolution and capacity increase are associated with a continuous growth and partial dissolution of the decomposition layer on the Li4Ti5O12 electrode during cyclic aging. Therefore, the high temperature formation approach could be the cornerstone for a cost-effective and easy commercialization of Li4Ti5O12-based cells. [Display omitted] •Formation of a protective decomposition layer on the LTO surface.•Improved electrochemical cell performance by high temperature formation.•Complete suppression of gas evolution during cyclic aging of LTO-based pouch cells.•Dynamic surface layer formation and gas evolution lead to capacity increase.