Vertically Aligned MoS2 Nanosheets Patterned on Electrochemically Exfoliated Graphene for High‐Performance Lithium and Sodium Storage

Abstract

Molybdenum disulfide (MoS 2) has been recognized as a promising anode material for high‐energy Li‐ion (LIBs) and Na‐ion batteries (SIBs) due to its apparently high capacity and intriguing 2D‐layered structure. The low conductivity, unsatisfied mechanical stability, and limited active material utilization are three key challenges associated with MoS 2 electrodes especially at high current rates and mass active material loading. Here, vertical MoS 2 nanosheets are controllably patterned onto electrochemically exfoliated graphene (EG). Within the achieved hierarchical architecture, the intimate contact between EG and MoS 2 nanosheets, interconnected network, and effective exposure of active materials by vertical channels simultaneously overcomes the above three problems, enabling high mechanical integrity and fast charge transport kinetics. Serving as anode material for LIBs, EG‐MoS 2 with 95 wt% MoS 2 content delivered an ultrahigh‐specific capacity of 1250 mA h g−1 after 150 stable cycles at 1 A g−1, which is among the highest values in all reported MoS 2 electrodes, and excellent rate performance (970 mA h g−1 at 5 A g−1). Moreover, impressive cycling stability (509 mA h g−1 at 1 A g−1 after 250 cycles) and rate capability (423 mA h g−1 at 2 A g−1) were also achieved for SIBs. The area capacities reached 1.27 and 0.49 mA h cm−2 at ≈1 mA cm−2 for LIBs and SIBs, respectively. This work may inspire the development of new 2D hierarchical structures for high efficiency energy storage and conversion.