Supercapattery: Merging of battery-supercapacitor electrodes for hybrid energy storage devices

Supercapattery devices have grasped attention due to their remarkable specific energy (Es) without affecting their specific power (Ps), which is significantly higher compared to batteries and supercapacitors (SCs). In contrast to the traditional electric double layer capacitors (EDLCs) and pseudocapacitors (PCs), supercapattery devices have shown larger specific capacitance. Metal oxides, sulfides, phosphates, and metal-organic frameworks (MOFs) based materials have been extensively utilized for the advancement of hybrid energy storage devices (HESDs). Currently the challenges faced by this technology, is to improve the energy density without compromising the power density. The advantage of two merged technologies (battery and supercapacitor (SC)) into a single system, delivered tremendous power from capacitive components while high specific energy from battery grade material (BGM). This review covers the most recent improvements in vastly used electrode materials, with significant capacity as well as long cyclic life for high-performance supercapattery devices. Furthermore, this study aims to elaborate the electrochemical performance of the metal oxides, sulfides, phosphates, and MOFs for energy storage applications.