Phase Evolution of Tin Nanocrystals in Lithium Ion Batteries
| Autor: | Yong Jae Cho, Jeunghee Park, Dong Myung Jang, Hyungsoon Im, Fazel Shojaei, Hong Seok Kang, Chan Su Jung, Young Rok Lim |
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| Rok vydání: | 2013 |
| Předmět: | |
| Zdroj: | ACS Nano. 7:11103-11111 |
| ISSN: | 1936-086X 1936-0851 |
| DOI: | 10.1021/nn404837d |
| Popis: | Sn-based nanostructures have emerged as promising alternative materials for commercial lithium-graphite anodes in lithium ion batteries (LIBs). However, there is limited information on their phase evolution during the discharge/charge cycles. In the present work, we comparatively investigated how the phases of Sn, tin sulfide (SnS), and tin oxide (SnO2) nanocrystals (NCs) changed during repeated lithiation/delithiation processes. All NCs were synthesized by a convenient gas-phase photolysis of tetramethyl tin. They showed excellent cycling performance with reversible capacities of 700 mAh/g for Sn, 880 mAh/g for SnS, and 540 mAh/g for SnO2 after 70 cycles. Tetragonal-phase Sn (β-Sn) was produced upon lithiation of SnS and SnO2 NCs. Remarkably, a cubic phase of diamond-type Sn (α-Sn) coexisting with β-Sn was produced by lithiation for all NCs. As the cycle number increased, α-Sn became the dominant phase. First-principles calculations of the Li intercalation energy of α-Sn (Sn8) and β-Sn (Sn4) indicate that Sn4Li(x) (x ≤ 3) is thermodynamically more stable than Sn8Li(x) (x ≤ 6) when both have the same composition. α-Sn maintains its crystalline form, while β-Sn becomes amorphous upon lithiation. Based on these results, we suggest that once α-Sn is produced, it can retain its crystallinity over the repeated cycles, contributing to the excellent cycling performance. |
| Databáze: | OpenAIRE |
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