Graphene nanowalls conformally coated with amorphous/ nanocrystalline Si as high-performance binder-free nanocomposite anode for lithium-ion batteries

• Published in: Journal of power sources Vol. 437; p. 226909
• Main Authors: Lin, Guanhua, Wang, Hongchun, Zhang, Ling, Cheng, Qijin, Gong, Zhengliang, Ostrikov, Kostya (Ken)
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.10.2019
• Subjects: Anode materials; Graphene nanowalls; Lithium-ion battery; Plasma nanotechnology; Silicon; Graphene nanowalls; Lithium-ion battery; Silicon; Plasma nanotechnology; Anode materials
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2019.226909

Silicon, one of the most promising candidates to replace graphite anodes in lithium-ion batteries (LIB), suffers from large volume change, structural instability, pulverization, shedding, and low conductivity. Here we present a LIB anode made of graphene nanowall (GNW) - Si nanocomposite (GNWs@Si). The GNWs featuring stable structure, large specific surface area, flexibility and excellent conductivity are grown by plasma-enhanced deposition directly on a Ni foam current collector. A mixed-phase silicon nano-layer is conformally and uniformly coated over the three-dimensional nanowall network, forming the GNWs@Si nanocomposite. Compared with conventional anodes, the GNWs@Si shows higher specific capacity, and better rate performance and capacity retention. The discharge specific capacities of the anodes made of pure Si and the GNWs@Si nanocomposite are 704.2 and 1116.2 mAh g−1, respectively. The GNWs@Si outperforms pure Si in the corresponding capacity retention (relative to the discharge specific capacity in the 4th cycle) by showing 79.1% after 200 cycles as opposed to 50.4% for Si. The GNWs@Si anode features large electrochemical reaction areas, short and fast transport paths for Li+ and electrons, relieved internal stress caused by Si volume expansion, and excellent electrochemical performance. [Display omitted] •New plasma-enabled approach for Li-ion battery anode fabrication.•Unique graphene nanowall-nanocrystalline Si nanocomposite anode.•Mitigates Si volume expansion and interfacial stress issues in common batteries.•Excellent electrochemical performance of anode in coin cell battery.•Scalability and compatibility with industrial fabrication platforms.