Beyond Theoretical Lithiation of the Anode Material Li4Ti5O12​

February 23, 2020
Beyond Theoretical Lithiation of the Anode Material Li4Ti5O12​
The energy storage mechanism in LTO. Results indicate Li insertion is not stopped at the expected “theoretical” capacity where the known 16c site is fully filled (Li7 state), as additional Li occupies the the new 48f site to reversibly increase the capacity to the Li8 state.

Scientific Achievement

It is shown that the accommodation of Li ions on a previously unexpected crystallographic site explains how the anode material LTO (Li4Ti5O12) can be reversibly lithiated from Li4 to Li8, beyond the expected maximum of Li7.​

Significance and Impact

The identification of the mechanism for enhanced Li capacity will guide future design and optimization of large-capacity anode materials for intercalation batteries.​

Research Details

  • Neutron diffraction resolved the structure and the crystallographic site occupancy of Li in LTO for different states of charge, in agreement with calculations and measured voltage profiles.​
  • Transmission electron microscopy showed the formation of a solid electrolyte interface layer during the initial charge cycle.​

Haodong Liu, Zhuoying Zhu, Jason Huang, Xin He, Yan Chen, Rui Zhang, Ruoqian Lin, Yejing Li, Sicen Yu, Xing Xing, Qizhang Yan, Xiangguo Li, Matthew J. Frost, Ke An, Jun Feng, Robert Kostecki, Huolin Xin, Shyue Ping Ong, and Ping Liu, “Elucidating the Limit of Li Insertion into the Spinel Li4Ti5O12,” ACS Materials Letters, 1, 96-102 (2019).