Recent advances, challenges, and prospects of piezoelectric materials for self-charging supercapacitor

Numerous important advancements toward developing a novel era of supercapacitors are being published in the past few years. There has been advancement in comprehending theory, synthesizing material, and designing devices concerning supercapacitors. The development of self-charging supercapacitors is rapidly gaining attention due to converting and storing energy in an integrated system. To address the energy shortage, studies have discovered novel techniques for integrating two devices (energy harvester and storage) to create a self-charged device (wearable/versatile electronics) suitable for various applications covering micro to macroscopic level (electric vehicles and fitness monitoring systems). We summarize state-of-the-art progress toward self-charging piezoelectric supercapacitors’ mechanism, materials, and various challenges. In this review, the central theme is a fundamental understanding of energy storage and energy harvesting mechanisms. Secondly, some emerging piezoelectric materials such as polyvinylidene difluoride (PVDF), siloxene, barium titanate (BaTiO₃), potassium-sodium niobate (K_0.5Na_0.5NbO₃), oxides, and bio-piezoelectric materials are discussed. The various challenges and future developments regarding further research in this thriving field have also been highlighted.