Abstract: Supercapacitors (SCs) have become a new bright spot in electrochemical power source due to their high power density, long cycling life and wide operation temperature. As the high-power density energy storage devices, SCs have been widely applied in electric vehicle, modern communication, aerospace, defense, and many other emerging fields. The markets for SCs are continuously increasing. However, the commercialization of SCs suffers from a lower energy density and higher cost. Thus, one great challenge for the supercapacitor (SC) technology is to improve the energy density without sacrificing the power density and cycle life. To address this critical issue, the worldwide SC researchers have focused on design of electrode materials, developments in new-type electrolyte and assemble method of device. Many significant breakthroughs in theoretical studies and engineering applications have been achieved. In this special issue, we collect eight submissions including review and research articles from the leading research groups in SCs. The recent progresses, future trends and new challenges in the field of SCs researches have been presented and highlighted. We hope that this special issue may attract more attention from researchers to focus their studies on this booming field, and to promote the research and development of SCs in China. We would like to take this opportunity to thank all the authors, reviewers, and editorial staffs of Journal of Electrochemistry for their excellent and professional contributions to this special issue.