Spaced-confined heterostructure engineering enables rapid ion transport in MoS2–Co9S8@C yolk-shell polyhedron for efficient lithium storage

Abstract

The out-of-plane van der Waals interaction between stack molybdenum sulfide layers is not conducive to ion transport in Li-ion capacitors, resulting in the decreasing cycling and rate performance. To improve the ion transfer ability, it is an effective strategy to optimize interatomic forces by using refined architectures to construct interface atomic structure. Herein, a space confined molybdenum sulfide-cobalt sulfide heterostructure embed in carbon (MoS2–Co9S8@C) with yolk-shell polyheron morphology is reported via a sequential ion exchanging strategy. The refined heterostructure facilitates to build strong built-in electric field, enabling high ion transport efficiency in MoS2–Co9S8@C polyhedron anode. The space confined yolk-shell structure contributes to buffer the volume expansion effect. Benefitting from the structural confinement engineering and electronic structural engineering, MoS2–Co9S8@C yolk-shell heterostructure shows the excellent pseudocapacitance performance. In this case, a full cell of MoS2–Co9S8@C//porous carbon lithium-ion capacitor shows a high working voltage of ∼4 V, and the maximum energy and power densities of ∼172 Wh kg−1 and 22, 500 W kg−1, respectively.