An Ultrahigh‐Capacity Dual‐Ion Battery Based on a Free‐Standing Graphite Paper Cathode and Flower‐Like Heterojunction Anode of Tin Disulfide and Molybdenum Disulfide

Abstract Dual‐ion batteries have been considered as a competitive energy‐storage device. However, owing to the lack of suitable high‐capacity density and rapid‐charging electrode materials, designing a cost‐effective and high‐performance dual‐ion battery is still a great challenge. Herein, an ultrahigh‐capacity dual‐ion battery is constructed based on a carbon‐nanotubes (CNTs) containing SnS 2 ‐MoS 2 @CNTs heterojunction anode and highly crystalline free‐standing graphite paper serves as cathode. The SnS 2 ‐MoS 2 @CNTs heterojunction consisting of ultrathin nanosheets was prepared via a facile two‐step hydrothermal method and shows flower‐like morphology and high crystallinity. Benefiting from the unique design concept, the graphite paper/SnS 2 ‐MoS 2 @CNTs dual‐ion battery delivers a high capacity of 274.2 mAh g −1 at 100 mA g −1 and has an outstanding capacity retention of 95 % after 300 cycles under 400 mA g −1 . Even at a high current density of 2 A g −1 the battery still retains a considerable capacity of 112.3 mAh g −1 . More importantly, the battery shows an extremely low self‐discharge of 0.006 % h −1 after resting for 24 h. Characterization using SEM and XRD further demonstrate the excellent cycling stability and good reversibility. Consequently, this constructed dual‐ion battery could be a promising energy storage device and provide new insights for the design of high‐performance dual‐ion batteries.