This product is a composite of disodium terephthalate and high surface area carbon nanosheets. With its low Na insertion voltage (0.2-0.6 V vs. Na⁺/Na), this material is a benchmark for counter electrode when developing new fast charging sodium-ion battery technologies, without risk of forming sodium dendrites. The composite is specially formulated to yield excellent contact of the active disodium terephthalate with the carbon black. This contact affords the high electronic conductivity and surface area that allows high capacity with a long cycle life. This electrode material was fabricated following sustainable procedures that minimize environmental impact. Further, it′s free of the toxic transition metals such as cobalt or nickel, thus a green alternative to conventional battery materials.