A diffusion encouraged core–shell heterostructured Co 3 Sn 2 @SnO 2 anode towards emerging dual ion batteries with high energy density

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Materials for energy and sustainability, 2021-07, Vol.9 (26), p.14991-15002
• Main Authors: Salunkhe, Tejaswi Tanaji, Kadam, Abhijit Nanaso, Kidanu, Weldejewergis Gebrewahid, Lee, Sang-Wha, Nguyen, Tuan Loi, Kim, Il Tae
• Format: Article
• Language: English
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/D1TA03496K

Lithium dual-ion batteries (LDIBs) are currently receiving great attention as energy-storage systems due to their low cost, environmentally friendly characteristics, and good safety features. Herein, mesoporous Co 3 Sn 2 and SnO 2 core–shell heterostructures (Co 3 Sn 2 @SnO 2 CSHs) were developed as new anode materials for LDIBs using diffusion-based nanocrystal conversion chemistry. LDIBs were configured using the 1 M LiPF 6 electrolyte, Co 3 Sn 2 @SnO 2 CSH anode, and expanded graphite (obtained by a simple ball milling process; so-called EG) cathode. After 200 cycles, the Co 3 Sn 2 @SnO 2 -EG LDIB delivered a reversible capacity of 90.0 mA h g −1 at 300 mA g −1 , a high coulombic efficiency of 93.3%, and an outstanding energy density of 334.5 W h kg −1 . These values demonstrate the feasibility of using LDIBs in various energy-related applications. Mechanisms are proposed to explain the intercalation/deintercalation of PF 6 − and Li + ions at different charge–discharge voltages and these are validated by Raman spectroscopy, X-ray diffraction, and elemental mapping. Finally, the superior electrochemical performance of the fabricated LDIBs could be attributed to the following reasons: (i) the large number of inner voids and mesopores in the CSHs improved reaction kinetics and structural stability. (ii) The hybrid composites exhibited a significantly high conductivity. (iii) Inactive Co effectively buffered against electrode pulverization and aggregation, thus enhancing the structural integrity of Co 3 Sn 2 @SnO 2 CSHs during the charge–discharge process. It is expected that these results will provide a new direction for the exploration of Co 3 Sn 2 @SnO 2 CSHs and probably other transition metal-based composites in LDIB development for scalable energy storage.