Layer-by-layer membranes for vanadium redox flow battery

Layer-by-layer (LbL) is a widely utilized method for enhancing the selectivity, efficiency, and long-term stability of ion exchange membranes (IEMs) in various applications. This technique involves the deposition of charged thin films on IEM surface through electrostatic interactions using polycations and polyanions. The simplicity and straightforwardness of the LbL modification technique make it a preferred choice due to its reduced preparation steps and time. This method is found to be suitable for preparation of IEMs with excellent vanadium barrier properties for vanadium redox flow battery (VRFB), a battery that is highly sought to promote renewable energy to the grid level. The objective of this article provides an overview for progress in the development of IEMs for VRFB using LbL method. This includes not only description of the basics of the LbL method and its pros and cons but also factors affecting membrane functions and stability. The current applications of various LbL prepared membranes in VRFB and the challenges to their performance are pointed out. The research future directions to enhance membranes characteristics are discussed. Overall, this short review offers valuable insights into the exploration of LbL techniques for the preparation of highly selective, efficient, and stable membranes for VRFB applications.