In-situ catalytic mechanism coupling quantum dot effect for achieving high-performance sulfide anode in potassium-ion batteries

Though numerous framework structures have been constructed to strengthen the reaction kinetics and durability, the inevitable generation of polysulfide dissolution during conversion-process can cause irreparable destruction to ion-channel and crystal structure integrality, which has become a huge obstacle to the application of metal-sulfide in potassium-ion batteries. Herein, the quantum dot structure with catalytic conversion capability is synchronously introduced into the design of FeS 2 anode materials to heighten its K + -storage performance. The constructed quantum dot structure anchored by the graphene with space-confinement effect can shorten the ion diffusion path and enlarge the active area, thus accelerating the K + -ions transmission kinetics and absorption action, respectively. The intermediate phase of formed Fe-nanoclusters possesses high-active catalysis ability, which can effectively suppress the polysulfide shuttle combined with the enhanced absorption effect, fully guaranteeing the structure stability and cycling reversibility. Predictably, the fabricated quantum dot FeS 2 can express a prominent advantage in rapid potassiation/depotassiation processes (518.1 mAh g −1 , 10 A g −1 ) and a superior cycling lifespan with gratifying reversible capacity at superhigh rate (177.7 mAh g −1 , 9000 cycles, 5 A g −1 ). Therefore, engineering quantum dot structure with self-induced catalysis action for detrimental polysulfide is an achievable strategy to implement high-performance sulfide anode materials for K-ions accommodation.