Jhansirani Kesavan

1 Introduction The increasing deployment of renewable-energy systems, portable electronics, wearable technologies, and electric transportation has intensified the demand for energy-storage technologies that combine low cost, safety, and environmental sustainability. Zinc-based energy-storage devices, including zinc-ion batteries (ZIBs), zinc-air batteries (ZABs), and zinc-ion hybrid capacitors (ZIHCs), have emerged as attractive alternatives to conventional lithium-based technologies.

1 Introduction The rapid deployment of renewable energy sources such as wind and solar power has driven the development of advanced energy storage systems, including supercapacitors, batteries, and fuel cells, which enable efficient energy storage and rechargeability [1-3]. Among them, the rechargeable (secondary) batteries play a crucial role in energy storage, with multiple charge-discharge ability through reversible redox reactions [4].