Closely packed Si@C and Sn@C nano-particles anchored by reduced graphene oxide sheet boosting anode performance of lithium ion batteries. (10th October 2021)

• Record Type: Journal Article
• Authors: Zhu, Chaoye; Zhang, Yao; Wu, Ziqiang; Ma, Zhihong; Guo, Xinli; Guo, Fuyi; Zhang, Jiakun; Li, Yushu
• Is Part Of: Journal of materials science & technology. Volume 87(2021)
• Page Start: 18
• Page End: 28
• Publication Date: 2021-10-10
• Subjects: Sn-Si-C nano-composites -- Anode -- Lithium ion batteries; Metals -- Periodicals; Materials science -- Periodicals; Materials science; Metals; Periodicals; 620.1105
• DOI: 10.1016/j.jmst.2020.12.075
• Languages: English
• ISSNs: 1005-0302

Abstract

Graphical abstract: Highlights: Si@C/Sn@C/rGO nanocomposite was synthesized via impregnation and hydrogenation reduction. Si@C/Sn@C/rGO delivers a reversible capacity of 1880 mA h g −1 after 60 cycles and high rate capability. Double core-shell structure effectively suppresses volume variation of electrodes. The preparation process is acid-free and environmentally friendly. Abstract: Both silicon and tin are promising anodes for new generation lithium ion batteries due to high lithium storage capacities (theoretically 4200 mA h g −1 and 992 mA h g -1, respectively). However, their large volumetric expansions (both are above 300 %) usually lead to poor cycling stability. In this case, we synthesized closely packed Si@C and Sn@C nano-particles anchored by reduced graphene oxide (denoted as Si@C/Sn@C/rGO) by the way of solution impregnation and subsequent hydrogenation reduction. Sn particles with a diameter of 100 nm are coated by carbon and surrounded by Si@C particles around 40 nm in average diameter through the high-resolution transmission electron microscopy. Expansions of Si and Sn are alleviated by carbon shells, and reduced graphene oxide sheets accommodate their volume changes. The prepared Si@C/Sn@C/rGO electrode delivers an enhanced initial coulombic efficiency (78 %), rate capability and greatly improved cycle stability (a high reversible capacity of nearly 1000 mA h g −1 is achieved after 300 cycles at a current density of 1000 mA g −1 ). It can be believed that packing Sn@C nano-particles with Si@C relieves the volume expansion of both and releases the expansion stresses. Sn@C particles enhance anode process kinetics by reducing charge transfer resistance and increasing lithium ion diffusion coefficient. The present work provides a viable strategy for facilely synthesizing silicon-tin-carbon composite anode with long life.