Three-Dimensional PrGO-Based Sandwich Composites With MoS2 Flowers as Stuffings for Superior Lithium Storage.

Yangqiang Zhao,Ying Weng,Yangyang Zhou,Ziying Zhang,Huizhen Zhang,Shisheng Xiong

doi:10.3389/fchem.2020.00094

Abstract

Graphene-based MoS2 nanocomposites are expected to be promising anode materials for lithium ion batteries because of their large specific capacity and high conductivity. However, the aggregation of graphene and the weak interaction between the two components hinder their practical application. Inspired by the sandwich structure, novel three-dimensional flower-like MoS2-PrGO sandwich composites were proposed as an advanced anode material for lithium-ion batteries. The separated 2D ultrathin rGO nano-sheets were connected by PEO chains and assembled into a well-organized 3D layered spatial structure, which not only avoids the aggregation of graphene but also accommodates a high mass loading of the micro-scale MoS2 nano-flowers. MoS2 nano-flowers with open architecture deliver large specific area. The rGO interlayers act as a conductive framework, making all flower-like MoS2 nano-stuffing electrochemically active. The ultra-thin 2D nano-sheets provide excellent cycle stability due to their neglectable volume changes during cycling. The 3D flower-like MoS2-PrGO sandwich composites deliver high energy density, excellent conductivity and stable cyclic performance during charge-discharge process. With a nearly 100% coulombic efficiency, their reversible capacity is retained at 1,036 mA h g−1 even after 500 cycles at current densities of 100 mA g−1. This novel design strategy provides a broad prospect for the development of advanced anode materials for superior lithium storage.

Highlights

Lithium-ion batteries have become the main power source of portable electronic products because of their high energy density, long cycle life, and eco-friendliness (Dunn et al, 2011; Fan et al, 2019; Zhang et al, 2019)
H2S released by sulfourea converted MoO24− and graphene oxide (GO) in situ to MoS2 nano-flowers and reduced GO (rGO) in the solvothermal process
The ultrathin MoS2 nanosheets were assembled into distinct nano-flowers anchored on the surfaces of rGO hosts

Summary

Introduction

Lithium-ion batteries have become the main power source of portable electronic products because of their high energy density, long cycle life, and eco-friendliness (Dunn et al, 2011; Fan et al, 2019; Zhang et al, 2019). More attentions have been paid to the exploration of electrode materials with high capacity and advanced performance (Ding et al, 2019; Zhang et al, 2019). Transition metal dichalcogenides (TMDs) have become a popular choice in the field of energy storage due to their graphene-like two-dimensional (2D) layered structure, in which lithium ions. Among a variety of TMDs, MoS2 is an ideal anode material for lithium ion batteries because its proper interlayer spacing endows this material a higher theoretical specific capacity (Kadam et al, 2019; Santhosha et al, 2019).

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Conclusion