Highly conductive carbon nanotube micro-spherical network for high-rate silicon anode

• Published in: Journal of power sources Vol. 394; pp. 94 - 101
• Main Authors: Park, Byung Hoon, Jeong, Jun Hui, Lee, Geon-Woo, Kim, Young-Hwan, Roh, Kwang Chul, Kim, Kwang-Bum
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.08.2018
• Subjects: High-rate Si anode; Lithium-ion batteries; Silicon/CNT microsphere; Spray dry; Lithium-ion batteries; Spray dry; High-rate Si anode; Silicon/CNT microsphere
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2018.04.112

We report on a highly conductive CNT micro-spherical network for high-rate silicon anode materials prepared by one-pot spray drying for lithium-ion batteries. The anode material contains silicon nanoparticles bound to CNTs through a small amount of sucrose-derived carbon. The first charge and discharge capacities of the Si/CNT/C microsphere electrode are measured to be 3152 and 2302 mA h g−1 of the composite, respectively, at 0.1 A g−1. The Si/CNT/C microsphere electrode exhibits an initial capacity of 1989 mA h g−1 at current density of 1.0 A g−1 and retains ∼70% of the initial capacity after 100 cycles. Even at a high current density of 10 A g−1, the Si/CNT/C microsphere electrode exhibits a capacity of 784 mA h g−1 with a stable charge/discharge behavior. The superior rate capability of the Si/CNT/C microsphere composites can be attributable to the unhindered Li-ion transport through the highly conductive CNT buffer matrix, to which Si NPs are strongly bound by the sucrose-derived carbon. These salient results give further impetus to the study of CNTs for use as a buffer matrix to improve the rate capability of high-capacity electrode materials with large volume changes during charge storage. •Si NPs are bound to CNT network through a very tiny amount of sucrose-derived carbon.•The Si/CNT/C microsphere has an interconnected pore facilitating Li-ion transport.•The Si/CNT/C microsphere exhibited superior rate capability with high capacity.