Cellulose microspheres have a wide range of applications due to their unique properties and versatility. Various preparation methods have been explored to tailor these microspheres for specific applications. Among these methods, the acetate method using cellulose acetate is well known. However, replacement of the acetate group through the butyrate group significantly extends the variety of morphological properties. In the present work, microspheres based on cellulose acetate butyrate are being developed with modified characteristics in terms of particle size, porosity, surface morphology and the inner structure of the microspheres. While the inner structure of cellulose acetate microspheres is predominantly porous, microspheres prepared from cellulose acetate butyrate are mainly filled or contain several smaller microspheres. Carbon materials from cellulose acetate butyrate microspheres exhibit a high specific surface area of 567 m² g⁻¹, even without further activation. Activation processes can further increase the specific surface area, accompanied by an adaptation of the pore structure. The prepared carbons show promising results in symmetrical supercapacitors with aqueous 6 M KOH electrolytes. Activated carbons derived from cellulose acetate butyrate microspheres demonstrate an energy density of 12 Wh kg⁻¹ at a power density of 0.9 kW kg⁻¹.

Biomass‐based materials have emerged as a promising alternative to the conventional graphite anode in Li‐ion batteries due to their renewability, low cost, and environmental friendliness. Therefore, a facile synthesis method for porous hard carbons based on cellulose acetate microspheres and bead cellulose is used, and their application as anode materials in Li‐ion batteries is discussed. The resulting porous carbons exhibit promising electrochemical characteristics, including a reversible capacity of about 300 mAh g⁻¹ at 0.1 C (37 mA g⁻¹) after 50 cycles, and stable capacities up to 210 mAh g⁻¹ over 1000 cycles at 1 C (372 mA g⁻¹) in half‐cells for cellulose acetate microspheres carbonised at 1200 °C. Moreover, at 60 °C cellulose‐derived carbons show higher specific capacities than graphite (300 mAh g⁻¹ vs 240 mAh g⁻¹ at 1 C after 500 cycles), indicating their potential for use in high‐temperature applications. The different charge storage mechanisms of the prepared hard carbon materials and graphite are observed. While capacity of graphite is mainly controlled by the Faradaic redox process, the cellulose‐derived carbons combine Faradaic intercalation and capacitive charge adsorption.