Cellulose, the most abundant biopolymer on Earth, is often celebrated for its role in paper, textiles, and packaging. Yet in the field of energy storage, cellulose is gaining attention not as the active energy-storing material itself but as a versatile, renewable backbone for a family of approaches that aim to improve sustainability, safety, and performance. This article surveys how cellulose and its derivatives are being harnessed to advance batteries and supercapacitors—from carbon materials derived from cellulose to bio-based binders, membranes, and gels. It also highlights what remains challenging and where the research frontier is heading.

Cellulose: A renewable backbone for energy storage innovations

Why cellulose matters in energy storage goes beyond its abundance. The polymer consists of glucose units linked by β-1,4-glycosidic bonds, forming a robust, crystalline fibril network. Its mechanical strength, chemical versatility, and the ability to tailor its properties through derivatization make it an attractive starting point for sustainable materials engineering. In energy storage, the appeal is twofold: first, cellulose and its derivatives can reduce environmental impact by replacing fossil-based precursors; second, they can improve device performance through enhanced porosity, binding, and mechanical integrity. Importantly, cellulose is not typically used as the primary active electrode material in most mainstream batteries today; rather, it serves as a renewable feedstock to produce carbon materials, binders, separators, and electrolytes that support the active materials and the overall cell performance.

Cellulose-derived carbon materials for energy storage

One of the most active research areas is converting cellulose into porous carbon architectures that can function as electrodes or host materials in energy storage devices. Pyrolysis of cellulose at controlled temperatures creates hard carbon or soft carbon with tunable porosity and surface chemistry. The resulting carbon can serve as:

• An anode material for lithium- and sodium-based batteries, where a porous carbon network facilitates ion transport and provides high surface area for charge storage.
• A component in supercapacitors, where high surface area and interconnected pores enable rapid charge-discharge cycles and high power densities.
• A host or additive that enhances electrode conductivity and structural stability, improving cycle life under demanding cycling conditions.

Compared with other biomass-derived carbons, cellulose-derived carbons offer a relatively uniform composition and can be processed to achieve well-defined pore structures. The choice of activation strategy (physical activation with steam or CO2, chemical activation with agents like KOH, or templating methods) allows tuning of micropores and mesopores, which in turn governs ion accessibility and storage capacity. Importantly, the carbonization process can be designed to minimize environmental impact by using the cellulose feedstock as a low-cost, renewable carbon source and by optimizing energy use during carbonization.

Insights into battery performance and design strategies

In lithium-ion and sodium-ion systems, cellulose-derived carbon often serves as a robust host for active materials or as a standalone anode material with a careful balance of carbon content, porosity, and surface functionalities. Some key design strategies include:

• Introducing heteroatoms (such as nitrogen or oxygen-containing groups) during or after carbonization to improve electronic conductivity and active site density.
• Creating hierarchical porosity (micro-, meso-, and macropores) to promote rapid ion transport and mitigate solid-electrolyte interphase formation.
• Compositing cellulose-derived carbon with metal oxides or sulfides to enhance capacity and cycling stability while maintaining structural integrity.

Beyond lithium-ion batteries, cellulose-derived carbons also show promise in emerging chemistries, including lithium–sulfur and sodium-sulfur systems, where porous carbon hosts help confine active sulfur species and manage volume changes during cycling. While performance is highly dependent on processing details, the overarching message is clear: cellulose is a versatile carbon precursor that can be tailored to meet specific energy-storage challenges while leveraging a renewable feedstock.

Cellulose as a binder and structural component in electrodes

In addition to becoming carbon, cellulose derivatives play critical roles as binders and structural additives in electrode formulations. The most widely used cellulose derivative is carboxymethyl cellulose (CMC), a water-soluble polymer that binds active materials to the current collector and maintains electrode integrity during cycling. CMC offers several advantages:

• It enables water-based processing, reducing reliance on organic solvents and improving environmental sustainability in electrode manufacturing.
• It can form cohesive networks that accommodate electrode swelling and volume changes, particularly in high-capacity anode materials such as silicon or other alloying systems.
• It can interact with active materials and conductive additives to improve interfacial stability and ionic transport within the electrode.

Moreover, other cellulose derivatives and nanostructured forms—such as cellulose ethers, nanofibrillated cellulose (CNF), and cellulose nanocrystals (CNC)—are explored as binders or reinforcement agents for composite electrodes. The goal is to achieve an electrode with lower binder content, improved mechanical resilience, and stable electrochemical performance across thousands of cycles.

Cellulose nanomaterials in electrolytes and separators

Cellulose-based nanomaterials bring unique mechanical and thermal properties that can support safer, more robust energy storage devices. Two notable avenues are:

• Reinforcement of polymer electrolytes: Incorporating CNF or CNC into polymer electrolyte matrices can enhance mechanical strength, reduce dendrite formation risks, and improve thermal stability. This is particularly relevant for solid or gel polymer electrolytes used in safe, high-voltage cells.
• Sustainable separators and membranes: Cellulose-based membranes, including those made from regenerated cellulose or cellulose derivatives like cellulose acetate, offer high thermal stability, selective ionic transport, and easy processing. These membranes can potentially replace some fossil-based separators in certain chemistries, contributing to safer and more environmentally friendly devices.

In addition to structural reinforcement, cellulose nanomaterials can influence electrolyte transport properties. Their high aspect ratio, intrinsic hydrophilicity, and surface functional groups provide pathways to tune porosity, wettability, and ion mobility, all of which contribute to overall cell performance and compatibility with different electrolytes.

Cellulose derivatives as gels and solid-state components

Beyond solid polymer electrolytes, cellulose derivatives are investigated for gel polymer electrolytes and flexible solid-state devices. Hydrophilic derivatives can form networks capable of immobilizing liquid electrolytes while maintaining ionic conductivity. In flexible or wearable energy storage technologies, the combination of cellulose-based gels with safe lithium or sodium chemistries can yield devices that balance mechanical comfort, safety, and energy density.

Why cellulose matters for sustainable energy storage

Cellulose-based approaches align with several strategic goals in energy storage research and development:

• Sustainability: Using renewable, bio-based feedstocks reduces dependence on petroleum-derived materials and lowers the carbon footprint of battery materials, when integrated responsibly along the supply chain.
• Green processing: Water-based processing of binders and coatings minimizes solvent emissions and improves worker safety, contributing to greener manufacturing pipelines.
• Performance flexibility: By controlling structure and chemistry at the nanoscale, cellulose materials can be engineered to tailor porosity, mechanical strength, and interfacial properties, supporting a range of chemistries—from conventional Li-ion to next-generation solid-state and Li–S systems.
• End-of-life considerations: Because cellulose is biodegradable under certain conditions and can be processed into recyclable carbon materials, it offers potential improvements in the lifecycle sustainability of energy storage devices when combined with responsible end-of-life strategies.

Limitations and challenges

Several hurdles must be addressed before cellulose-based components become ubiquitous in commercial batteries and capacitors. Some of the key challenges include:

• Density and volumetric energy: While cellulose-derived carbons can deliver competitive gravimetric capacities, achieving high volumetric energy density requires careful control of pore structure and density, which adds processing complexity.
• Consistency of bio-based feedstocks: Natural variability in cellulose sources can lead to batch-to-batch differences in carbon yields and material properties. Standardization and robust processing are essential.
• Compatibility with existing chemistries: Integrating cellulose-derived materials with high-voltage cathodes, fast-charging protocols, or aggressive electrolytes demands thorough compatibility testing and potential protective interphases.
• Scaling up and cost: While cellulose itself is inexpensive, the processing routes (e.g., precise activation, templating, or nanostructuring) can add cost and energy input. Lifecycle analyses are needed to confirm net environmental benefits at scale.
• Stability under cycling: For binders like CMC, swelling, mechanical degradation, or chemical interactions with electrolytes can impact long-term performance. Optimizing binder concentration and co-additives is critical.

Future prospects and research directions

The future of cellulose in energy storage likely lies in integrated, multi-material systems that leverage the strengths of cellulose-derived carbons, binders, and separators. Promising directions include:

• Hierarchical materials design: Combining cellulose-derived carbon with metal oxides, sulfides, or alloys to create composite electrodes with improved capacity, rate capability, and cyclability.
• Advanced cellulose nanomaterials: Further development of CNF and CNC as functional components in nanostructured electrodes, reinforcing layers, and gel electrolytes to enhance performance while maintaining sustainability.
• Green processing and circular economy integration: Developing scalable, water-based processing routes, low-temperature activation methods, and recycling strategies that maximize material recovery and minimize waste.
• Smart, responsive materials: Exploring cellulose-based matrices that adapt to operating conditions, potentially enabling safer high-energy-density devices with self-healing or adaptive interphases.
• Cross-disciplinary optimization: Collaboration across chemistry, materials science, chemical engineering, and life-cycle assessment to quantify environmental benefits and drive cost-effective adoption.

Takeaways

• Is cellulose used for energy storage? Yes, primarily as a renewable source for carbon materials, as well as for binders, separators, and gel electrolytes that underpin battery and supercapacitor performance.
• Cellulose-derived carbons offer tunable porosity and surface chemistry, enabling improved storage capabilities in batteries and high-power devices in supercapacitors.
• Binders such as carboxymethyl cellulose enable water-based electrode processing, reducing solvent use and improving interfacial stability in many electrode systems.
• Cellulose nanomaterials can reinforce electrolytes and separators, contributing to safer, mechanically robust energy storage devices, especially in solid-state and gel systems.
• Realizing the full potential of cellulose in energy storage requires addressing variability in bio-feedstocks, processing costs, and compatibility with high-energy chemistries, while maintaining a lifecycle and sustainability focus.

In summary, cellulose is not a magic battery material by itself, but it is a powerful enabler of greener, safer, and potentially higher-performance energy storage technologies. By converting a ubiquitous natural polymer into carbon frameworks, binding networks, and separator components, researchers are opening pathways to more sustainable energy storage ecosystems without sacrificing the performance demanded by modern devices. As the field matures, the role of cellulose is likely to expand across multiple chemistries and device architectures, contributing to a more resilient and environmentally conscious energy storage landscape.