Flexible and robust silicon/carbon nanotube anodes exhibiting high areal capacities

Abstract

The fast development of flexible devices has greatly boosted the demands for flexible lithium-ion batteries (LIBs). Accordingly, a broad exploration of flexible electrodes in LIBs is crucial. At present, the major challenge in the flexible electrode for lithium-ion batteries (LIBs) is how to achieve an excellent electrochemical performance (particularly high-energy density) while maintaining superior mechanical flexibility. Herein, flexible silicon/carbon nanotube (Si/CNT) electrode is prepared via a common blade-coating, which is adoptable to large-scale production. The CNT network from monodispersed CNT solution endows the electrode with superior tensile strength and mechanical toughness. The tensile strength of the flexible electrodes is up to 3.75 MPa, and the corresponding strain at break is 43.9%. The flexible electrode delivers an areal capacity of 10.6 mAh cm−2 at 0.06 mA cm−2, which is completely meet the practical requirement (1–3 mAh cm−2). And a high reversible capacity of 5.64 mAh cm−2 can be retained at 0.3 mA cm−2 after 200 cycles. In addition, the pouch cell exhibits a promising cycling stability under the repeated deformation state. Moreover, this work also provides a feasible and scalable method to fabricate flexible electrodes for other wearable energy storage systems.