An Ultrahigh-Capacity Dual-Ion Battery Based on a Free-Standing Graphite Paper Cathode and Flower-Like Heterojunction...

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 SnS₂ -MoS₂ @CNTs heterojunction anode and highly crystalline free-standing graphite paper serves as cathode. The SnS₂ -MoS₂ @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/SnS₂ -MoS₂ @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.