Rational design and synthesis of nanosheets self-assembled hierarchical flower-ball-like CuFeS_(2)for boosted wide temperature sodium-ion batteries

Nano-structure designs with conductive networks have been demonstrated as an efficient strategy to boost sodium storage properties for transition metal sulfides.Herein,an exquisite nanosheets self-assembled hierarchical flower-ball-like CuFeS_(2)embedded into the reduced graphene oxide(RGO)nanosheet matrix(F-CuFeS_(2)@RGO)is fabricated via a concise two-step solvothermal method.Such a well-designed architecture affords increased active reaction interfaces and enhanced mixed ionic/electronic conductivity.Meanwhile,the external RGO matrix can effectively alleviate the volume expansion and create a stable structure during long cycles.As a result,the composite material exhibits a high reversible capacity of 559 mAh·g^(-1)at 0.1 A·g^(-1),a superior rate capability of 455 mAh·g^(-1)at 5 A·g^(-1)and excellent cyclic stability with 96%capacity retention after 4800 cycles at 5 A·g^(-1),among the best in the state-of-the-art transition metal sulfide anodes.Especially,F-CuFeS_(2)@RGO delivers outstanding low-temperature performances with a high capacity retention of 100%and 91%at-20 and-40℃,respectively,over 200 cycles.The proposed hierarchical structure fabrication paves a new direction in the design of high-performance electrodes for all-temperature energy storage applications.