Atomistic Conversion Reaction Mechanism of WO3 in Secondary Ion Batteries of Li, Na, and Ca

Yang He; Meng Gu; Haiyan Xiao; Langli Luo; Yuyan Shao; Fei Gao; Yingge Du; Scott X Mao; Chongmin Wang

doi:10.1002/anie.201601542

Atomistic Conversion Reaction Mechanism of WO3 in Secondary Ion Batteries of Li, Na, and Ca

Angew Chem Int Ed Engl. 2016 May 17;55(21):6244-7. doi: 10.1002/anie.201601542. Epub 2016 Apr 13.

Authors

Yang He¹, Meng Gu², Haiyan Xiao³, Langli Luo², Yuyan Shao⁴, Fei Gao⁵, Yingge Du⁶, Scott X Mao⁷, Chongmin Wang⁸

Affiliations

¹ Department of Mechanical Engineering and Materials Science, University of Pittsburgh, Pittsburgh, PA, 15261, USA.
² Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA, 99352, USA.
³ School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu, 610054, China.
⁴ Energy and Environmental Directorate, Pacific Northwest National Laboratory, Richland, WA, 99352, USA.
⁵ Department of Nuclear Engineering and Radiological Sciences, University of Michigan, Ann Arbor, MI, 48109, USA. gaofeium@umich.edu.
⁶ Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA, 99352, USA. yingge.du@pnnl.gov.
⁷ Department of Mechanical Engineering and Materials Science, University of Pittsburgh, Pittsburgh, PA, 15261, USA. sxm2@pitt.edu.
⁸ Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA, 99352, USA. chongmin.wang@pnnl.gov.

PMID: 27071488
DOI: 10.1002/anie.201601542

Abstract

Intercalation and conversion are two fundamental chemical processes for battery materials in response to ion insertion. The interplay between these two chemical processes has never been directly seen and understood at atomic scale. Here, using in situ HRTEM, we captured the atomistic conversion reaction processes during Li, Na, Ca insertion into a WO3 single crystal model electrode. An intercalation step prior to conversion is explicitly revealed at atomic scale for the first time for Li, Na, Ca. Nanoscale diffraction and ab initio molecular dynamic simulations revealed that after intercalation, the inserted ion-oxygen bond formation destabilizes the transition-metal framework which gradually shrinks, distorts and finally collapses to an amorphous W and Mx O (M=Li, Na, Ca) composite structure. This study provides a full atomistic picture of the transition from intercalation to conversion, which is of essential importance for both secondary ion batteries and electrochromic devices.

Keywords: WO3; conversion; intercalation; in situ TEM; ion batteries.

Publication types

Research Support, U.S. Gov't, Non-P.H.S.