Defective 1T′-ReSe2 nanosheets vertically grown on elastic MXene for fast and stable potassium ion storage

Abstract

The sluggish reaction kinetics and poor structure stability of transition metal dichalcogenides (TMDs)-based anodes in potassium-ion batteries (KIBs) usually cause limited rate performance and rapid capacity decay, which seriously impede their application. Herein, we report a vacancy engineering strategy for preparing a class of Te-doped 1T’-ReSe2 anchored onto MXene (Te-ReSe2/MXene) as an advanced anode for KIBs with high performance. By taking advantage of the synergistic effects of the defective Te-ReSe2 arrays with expanded interlayers and the elastic MXene nanosheets with self-autoadjustable function, the Te-ReSe2/MXene superstructure exhibits boosted K+ ion storage performance, in terms of high reversible capacity (361.1 mA h g−1 at 0.1 A g−1 over 200 cycles), excellent rate capability (179.3 mA h g−1 at 20 A g−1), ultra-long cycle life (202.8 mA h g−1 at 5 A g−1 over 2000 cycles), and steady operation in flexible full battery, presenting one of the best performances among the TMDs-based anodes reported thus far. The kinetics analysis and theoretical calculations further indicate that satisfactory pseudocapacitive property, high electronic conductivity and outstanding K+ ion adsorption/diffusion capability corroborate the accelerated reaction kinetics. Especially, structural characterizations clearly elaborate that the Te-ReSe2/MXene undergoes reversible evolutions of an initial insertion process followed by a conversion reaction.