Recent Development of Metallic (1T) Phase of Molybdenum Disulfide for Energy Conversion and Storage

The development of a feasible and inexpensive strategy to obtain and utilize sustainable energy is an important issue for the sustainable development of human society. Over the past decade, significant progress has been made in the development of novel functional materials for energy conversion and storage. Owing to their unique physico-chemical properties, 2D layered materials, such as graphene and transition metal dichalcogenides, have attracted great interest in energy-related research. 1T-MoS2 is a metallic phase of molybdenum disulfide (MoS2) with extraordinary electronic conductivity, enlarged interlayer spacing, and more electrochemically active sites along the basal plane, which offers intriguing benefits for energy-related applications compared to its semiconducting counterpart (2H-MoS2). This review summarizes the preparation and structure-property relationships of 1T-MoS2, as well as the underlying relations between the metallic (1T) and semiconducting (2H) phases of MoS2. Recent progress in the preparation and stabilization of 1T-MoS2 materials and their applications for energy conversion and storage are discussed, including water splitting to form hydrogen via photo/electrocatalysis and electricity storage in lithium-ion batteries, sodium-ion batteries, magnesium-ion batteries, and supercapacitors. Optimization strategies of 1T-MoS2 to obtain enhanced practical properties based on theoretical calculations are also presented.