Roadmap for Next-Generation Electrochemical Energy Storage Technologies: Secondary Batteries and Supercapacitors.

The transition from fossil fuels to environmentally friendly renewable energy sources is crucial for achieving global initiatives such as the carbon peak and carbon neutrality. The use of secondary batteries and supercapacitors based on electrochemical energy storage principles provides high energy density, conversion efficiency, and rapid response times, offering essential solutions for stabilizing and ensuring the reliability of energy supply from renewable sources despite their intermittency. In recent years, increased demands for higher energy density, improved rate performance, longer cycle life, enhanced safety, and cost-effectiveness have driven researchers to delve deeper into electrode materials, electrolytes, and storage mechanisms in secondary batteries. This effort has led to various modification techniques and rapid advancements in next-generation secondary batteries, which are presented in this roadmap. The design principles, research advancements, and failure mechanisms of component materials of high-energy-density lithium-ion batteries, sodium/potassium-ion batteries, multivalent metal-ion batteries, alkali metal batteries, metal-sulfur batteries, metal-air batteries, solid-state batteries, redox flow batteries, and supercapacitors are systematically summarized. More importantly, the potential future solutions are suggested to narrow the gap between the current energy storage systems and future demands of practical grid-scale energy storage, thereby promoting their widespread application.