Construction of Rich Conductive Pathways from Bottom to Top: A Highly Efficient Charge-Transfer System Used in Durable Li/Na-Ion Batteries at -20 °C.

Abstract

The construction of potential electrode materials with wide temperature property for high-energy-density secondary batteries has attracted great interest in recent years. Herein, a hybrid electrode, consisting of a nitrogen-doped carbon/α-MnS/flake graphite composite (α-MnS@N-C/FG), is prepared through a post-sulfurization route. In the α-MnS@N-C/FG composite, α-MnS nanoparticles wrapped by the N-C layer are uniformly embedded onto FG, forming a novel nanofoam structure. The as-obtained α-MnS@N-C/FG shows excellent lithium/sodium storage performance, with a specific capacity of 712 mA h g-1 in the 700th cycle at 1.0 A g-1 or 186.4 mA h g-1 in the 100th cycle at 100 mA g-1 using lithium or sodium foil as the counter electrode, respectively. Moreover, even operated at -20 °C, the α-MnS@N-C/FG can still attain a high specific capacity of 350 mA h g-1 after 50 cycles at 100mA g-1 for LIBs. This exceptional electrochemical response is attributed to the synergetic effect of the smart design of a hybrid nanofoam structure, in which the FG skeleton and N-C coating layer can significantly enhance the conductivity of the whole electrode from bottom to top. Accordingly, the enhanced redox kinetics endow the electrode with pseudocapacitive-dominated electrochemical behavior, leading to fast electrode reactions and robust structural stability in the whole electrode.