Structural engineering of SnS2/Graphene nanocomposite for high-performance K-ion battery anode

K-ion batteries (KIBs) are drawing increasing research interest as a promising supplement of Li-ion batteries due to the natural abundance of K resource. However, due to the large size of K+, high-capacity anodes are challenged by the structural stability of the active materials which are susceptible to large volumetric deformation after incorporating with a sufficient number of K+. Herein, using SnS2/graphene as an example, we demonstrated that high-performance KIBs anode could be achieved through collaborative efforts targeting on both the active material and the prepared electrode film. The electrochemically-active species of SnS2 were controlled into small nanoparticles with their size below 5 nm to provide sufficient reactive sites for K+ storage. Meanwhile, highly-resilient electrode film based on the prepared SnS2/graphene nanocomposite was built on aluminum (Al) current collector rather than the widely-used copper foil, forming a strong anode film with high peel strength to endure the potassiation/depotassiation process. In this way, the active species was able to deliver an extraordinary reversible capacity of 610 mAh g(-1) with unprecedented high-rate capability (around 290 mAh g(-1) at 2A g(-1)) and promising cycling stability. This contribution sheds light on the rational design of high-performance electrode for KIBs and beyond.