Electrochemical Energy Storage: Defect Engineering of 2D Materials for Electrochemical Energy Storage (Adv. Mater. Interfaces 15/2020)

In article number 2000494, Wen Lei, Haijun Zhang, and co-workers want to express that the existence of defects (vacancies or heteroatom) can significantly enhance the electrochemical activity of 2D materials in energy storage. Specifically, the superlative performance of energy storage devices along the metrics of large capacity, long term cycling stability, and high electrocatalytic reactivity are derived from the following remarkable features of the defective 2D materials: (1) The introduction of defects can increase the surface area by extending the interlayer distance of 2D materials, and the existence of vacancies provide abundant ion diffusion channel, all of which result in higher capacity. (2) The existence of defects contributes extra capacitance by introducing additional faradaic pseudocapacitance or more exposed electrochemical active sites. Additionally, the introduction of defects can further enhance adsorption capacity for polysulfides which improve both capacity and cycling stability of Li-S batteries. (3) The incorporation of heteroatom can further enhance the electrical conductivity of 2D materials.