Fe–Si networks and charge/discharge-induced phase transitions in Li2FeSiO4 cathode materials
| Autor: | Zi-Zhong Zhu, Manh Cuong Nguyen, Zijing Lin, Xin Zhao, Cai-Zhuang Wang, Kai-Ming Ho, Xiaobao Lv, Shunqing Wu |
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| Rok vydání: | 2018 |
| Předmět: |
Phase transition
Work (thermodynamics) Materials science General Physics and Astronomy Charge (physics) 02 engineering and technology Crystal structure 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences Cathode 0104 chemical sciences law.invention Chemical physics law Formula unit Atom Physical and Theoretical Chemistry 0210 nano-technology Charge discharge |
| Zdroj: | Physical Chemistry Chemical Physics. 20:14557-14563 |
| ISSN: | 1463-9084 1463-9076 |
| DOI: | 10.1039/c8cp01962b |
| Popis: | Structural phase transitions of electrode materials are responsible for poor reversibility during charge/discharge cycling in Li-ion batteries. Using previously developed structural databases, we investigate a structural landscape for LixFeSiO4 systems at x = 1. Starting with low-energy Li2FeSiO4 crystal structures, we explore the crystal structures of the material in different states of charge. The as-prepared Li2FeSiO4 materials adopt low energy structures characterized by two-dimensional (2D) Fe-Si networks. After the removal of one Li per formula unit to form LiFeSiO4, the structures with three-dimensional (3D) diamond-like Fe-Si networks become more energetically favorable without a significant impact on the charge capacity, which agrees with previous experimental and theoretical work. However, we reveal that the structure with a 3D diamond-like Fe-Si network can further transform into a new structure at x = 1. And the Li atom is hard to reinsert into these new structures. Consequently the system is prevented from returning to the Li2FeSiO4 state. We believe that the formation of this new structure plays an important role in the loss of reversible capacity of Li2FeSiO4 electrode materials. |
| Databáze: | OpenAIRE |
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