Transition metal pyrophosphate (MxP2O7): A new arrival in hybrid supercapacitors

Transition metal pyrophosphates (TMPs) is a novel family of materials that gaining significant interest as a promising electrode for supercapacitors (SCs) owing to its significant redox-active functionality, excellent chemical and thermal stability, superior electrical conductivity, cheap cost and layered structure. Recently, various attempts have been undertaken to design and engineer TMPs (MxP2O7 where M = Ni, Co, Cu, Mn, Zn, Ti and Fe) for high-performance SCs. This review highlights the key progress with an emphasis on the design strategies, structural features and their potential applications in SCs. The electrochemical characteristics of TMPs can be effectively tailored by diverse inventive ways like doping, creating nanostructures and core–shell heterostructures. The potential of TMPs as a positive electrode in the hybrid SCs highlighted to comprehend the operational importance of these materials. Lastly, the challenges and prospects are discussed for the advancement of high TMPs for SCs. The comprehensive understanding of the structure–property-performance correlation gives a directions for the development of TMPs based next-generation energy storage devices.