Dual conductive network-enabled graphene/Si–C composite anode with high areal capacity for lithium-ion batteries

• Published in: Nano energy Vol. 6; pp. 211 - 218
• Main Authors: Yi, Ran, Zai, Jiantao, Dai, Fang, Gordin, Mikhail L., Wang, Donghai
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Ltd 01.05.2014; Elsevier
• Subjects: Applied sciences; Batteries; Capacitors. Resistors. Filters; Cross-disciplinary physics: materials science; rheology; Direct energy conversion and energy accumulation; Electrical engineering. Electrical power engineering; Electrical power engineering; Electrochemical conversion: primary and secondary batteries, fuel cells; Electrodes; Exact sciences and technology; Fullerenes and related materials; diamonds, graphite; Graphene/silicon/carbon composites; Materials; Materials science; Microstructures; Physics; Specific materials; Various equipment and components; Electrodes; Graphene/silicon/carbon composites; Batteries; Microstructures; Lithium ion batteries; Gravimetric analysis; Anode; Carbon; Composite material; Graphene/silicon/ carbon composites; Lithium battery; Graphite; Capacitance; Silicon
• ISSN: 2211-2855
• DOI: 10.1016/j.nanoen.2014.04.006

Silicon has been regarded as one of the most promising alternatives to the current commercial graphite anode for Li-ion batteries due to its high theoretical capacity and abundance. Although high gravimetric capacity (mAh/g) of Si-based materials can be achieved, areal capacity (mAh/cm2), an indication of the energy stored at the electrode level, has rarely been discussed. Herein, a novel micro-sized graphene/Si–C composite (G/Si–C) is reported, in which micro-sized Si–C particles are wrapped by graphene sheets. Owing to dual conductive networks both within single particles formed by carbon and between different particles formed by graphene, low electrical resistance can be maintained at high mass loading, which enables a high degree of material utilization. Areal capacity thus increases almost linearly with mass loading. As a result, G/Si–C exhibits a high areal capacity of 3.2mAh/cm2 after 100 cycles with high coulombic efficiency (average 99.51% from 2nd to 100th cycle), comparable to that of commercial anodes. The current findings demonstrate the importance of building a conductive network at the electrode level to ensure high material utilization at high mass loading and may shed light on future designs of Si-based anodes with high areal capacity. [Display omitted] •Micro-sized graphene/Si–C composite (G/Si–C) is studied as a Li-ion anode material.•In the composite micro-sized Si–C particles are wrapped by graphene sheets.•G/Si–C has dual conductive networks at both material and electrode level.•G/Si–C shows a high degree of material utilization at high mass loading.•An areal capacity of 3.2mAh/cm2 after 100 cycles is achieved by G/Si–C.