Biomass-derived carbon dots (BCDs) have attracted considerable attention for their promising attributes, including low toxicity, excellent solubility, biocompatibility, and eco-friendliness. Their rich surface chemistry and impressive photoluminescent properties have sparked widespread research interest, particularly in areas such as sensing and biomedicine. However, the potential applications of BCDs in the energy sector, especially in electrochemical energy storage batteries, have received scant review focus. This article systematically consolidates the selection of carbon sources, synthesis methods, modification strategies, and the corresponding characterization techniques for BCDs. Application strategies in energy storage batteries are explored, with the underlying connection between the role of BCDs in batteries and their structural properties being analyzed, providing comprehensive insights from synthesis and characterization to application. Furthermore, a preliminary discussion is initiated on the current limitations in material regulation and design within research, and potential avenues for enhancement are proposed.