The burgeoning global economy during the past decades gives rise to the continuous increase in fossil fuels consumption and rapid growth of CO2 emission,which demands an urgent exploration into green and sustainable devices for energy storage and power management.Supercapacitors based on activated carbon electrodes are promising systems for highly efficient energy harvesting and power supply,but their promotion is hindered by the moderate energy density compared with batteries.Therefore,scalable conversion of CO2 into novel carbon nanostructures offers a powerful alternative to tackle both issues:mitigating the greenhouse effect caused by redundant atmospheric CO2 and providing carbon materials with enhanced electrochemical performances.In this tutorial review,the techniques,opportunities and barriers in the design and fabrication of advanced carbon materials using CO2 as feedstock as well as their impact on the energy-storage performances of supercapacitors are critically examined.In particular,the chemical aspects of various CO2 conversion reactions are highlighted to establish a detailed understand-ing for the science and technology involved in the microstructural evolution,surface engineering and porosity control of CO2-converted carbon nanostructures.Finally,the prospects and challenges associated with the industrialization of CO2 conversion and their practical application in supercapacitors are also discussed.