Montmorillonite-based materials for electrochemical energy storage

Using low cost and resource-rich natural materials to develop vital components, especially electrodes, separators, and solid/quasi-solid electrolytes, is of great significance for the commercial application of electrochemical energy storage (EES) devices. Montmorillonite (MMT), although it is a unremarkable traditional clay mineral material, has increasingly attracted widespread interest in the EES field, which is mainly attributed to its low cost, abundant resources, tuneable two-dimensional (2D) layered structure, unique ionic conductive properties, high specific surface area and so on. The focus of this review is to provide a specific and comprehensive summary of the recent progress of MMT-based materials in the field of EES. Firstly, the structure and physicochemical properties of MMT clay are discussed from the perspective of structure-property relationships. Subsequently, the main focus is on the research progress of MMT-based materials in the vital components of EES devices (mainly metal (Li/Na/Zn)-ion batteries, Li-S batteries, and supercapacitors), wherein the role of MMT in different components of EES devices has been elaborated through various characterization analyses and theoretical calculations. Finally, a short conclusion along with some possible future research directions of MMT-based materials in high-performance EES devices is proposed. This review tries to provide beneficial guidance for the practical application of MMT-based functional materials in EES. Montmorillonite is widely applied in the field of electrochemical energy storage mainly due to its low cost, inherent high ionic conductivity, tuneable 2D layered structure, and abundant chemisorption active sites.