Highly active and stable Cu9S5-MoS2 heterostructures nanocages enabled by dual-functional Cu electrocatalyst with enhanced potassium storage

Abstract

• Cu 9 S 5 /MoS 2 hollow nanocage heterostructure was studied as anode material for potassium-ion batteries. • Rational introduced Cu 0 intermediates effectively anchor K x S y polysulfides and facilitate rapid charge transfer. • Unique Cu 9 S 5 /MoS 2 nanocage showed superior conversion reaction reversibility in K-storage application. The intrinsic poor electrical conductivity, severe dissolution of K x S y intermediates, and inferior conversion reaction reversibility extremely impede the practical application of the transition-metal chalcogenides (TMDs) anode for potassium-ion batteries (PIBs). Herein, a rationally designed Cu 9 S 5 /MoS 2 /C heterostructure hollow nanocage was synthesized with assistance from metal-organic frameworks (MOFs) precursor. During the K-storage process, the homogeneously distributed the sulfiphilic nature of Cu 0 reaction product could act as a dual-functional catalyst, not only facilitating the rapid charge transfer but also effectively anchoring (K x S y ) polysulfides, thus boosting K-storage reactions reversibility during the conversion reaction process. When applied as an anode for PIBs, the as-prepared heterostructure exhibits excellent reversible capacity and long cycle lifespan (350.5 mAh g –1 at 0.1 A g –1 and 0.04% per cycle capacity decay at 1 A g –1 after 1000 cycles). Additionally, the potassium storage mechanism is distinctly revealed by in-situ characterizations. The nanoarchitecture designing strategy for the advanced electrode in this work could provide vital guidance for relevant energy storage materials. The hollow Cu9S5/MoS2/C nanocage has been rational designed and regarded as an anode material for potassium-ion batteries (PIBs). Due to the dual-functional catalytic effects of in-situ formed Cu0 nanograin during conversion reaction and homogeneously distributed heterointerfaces within Cu9S5/MoS2, the poor charge transfer, severe dissolution of KxSy polysulfides, and inferior phase transformation reaction reversibility can be significantly improved. It can not only strengthen the integral stability, but also enhance the K-storage properties with long-life and high-capacity.