Coal-derived graphene foam and micron-sized silicon composite anodes for lithium-ion batteries. (1st December 2022)

• Record Type: Journal Article
• Authors: Zhang, Xin; Wang, Huan; Pushparaj, Robert Ilango; Mann, Michael; Hou, Xiaodong
• Is Part Of: Electrochimica acta. Volume 434(2022)
• Publication Date: 2022-12-01
• Subjects: Silicon anode -- Graphene foam -- Humic acid -- Micron-sized silicon -- Lithium-ion battery; Electrochemistry -- Periodicals; Electrochemistry, Industrial -- Periodicals; 541.37
• DOI: 10.1016/j.electacta.2022.141329
• Languages: English
• ISSNs: 0013-4686

Abstract

Abstract: Silicon-based materials demonstrate significant potential as lithium-ion batteries (LIBs) anode, but their expansion and degradation present engineering design challenges for commercial application. In this study, a porous three-dimensional (3D) graphene and micron-sized silicon composite anode (Si@G foam) was synthesized using humic acid (HA) derived from coal as a graphene precursor. In-situ formation of graphene structure through reducing HA was confirmed by Raman spectra. The reduced HA (rHA) shows similar electrical conductivity compared to the commercial conductive carbon. SEM images depict a 3D skeleton of coal-derived graphene, with silicon particles distributed on the 3D graphene foam's internal surface. The Si@G composite-anode displays a good reversible capacity of ∼656 mAh/g at a current density of 50 mA/g, as well as a high-rate capability of ∼433 mAh/g at a current density of 800 mA/g, and outstanding cycling stability –89.8% capacity retention after 300 cycles, which is significantly higher than that of other foam structures. During lithiation and de-lithiation, the graphene foam serves as a matrix of electrical conductors and a volume expansion support for silicon. This 3D graphene network will be beneficial for developing advanced silicon-based anodes for high-performance LIBs.