Carbon Nanotube-Graphene Composite Materials for Energy Storage

Carbon nanotube-graphene composites integrate one-dimensional nanotubes and two-dimensional graphene into three-dimensional architectures that exploit the high electrical conductivity, large specific surface area and mechanical robustness of both constituents. In these composites, carbon nanotubes act as spacers to prevent restacking of graphene sheets while providing conductive pathways, and graphene layers serve as flexible, high-surface-area substrates with tunable porosity. This synergistic combination enhances charge storage by maximising accessible surface area for ion adsorption, improving electron-transport networks and accommodating volume changes during cycling. Fabrication methods range from chemical vapour deposition and solution-based assembly to in situ growth techniques, often incorporating heteroatom doping or templating strategies to tailor pore structure and surface chemistry. Such materials have demonstrated superior performance in supercapacitors—offering high capacitance, rapid charge–discharge rates and long cycle life—and as electrode supports in lithium- and sodium-ion batteries, where they facilitate stable electrode–electrolyte interfaces and high-rate capabilities. Recent advances have focused on scalable synthesis, hierarchical porosity control, multifunctional doping and integration into flexible or miniaturised devices, underscoring their potential for next-generation energy storage systems.

Research from Nature Portfolio

Recent studies have developed quantitative models and experimental demonstrations of the synergistic conductivity in carbon nanotube–graphene hybrids. A predictive framework was introduced to calculate the numbers of nanotube–nanotube, graphene–graphene and nanotube–graphene contacts in randomly dispersed composites, revealing an optimal composition at which the total interparticle connectivity—and hence the electrical conductivity—is maximised. Inkjet-printed films based on this model exhibited higher conductivity than films of pure nanotubes or graphene at specific mixing ratios, confirming that controlled hybridisation can produce superior charge-transport networks essential for high-power energy storage devices.

Carbon Nanotube-Graphene Composite Materials for Energy Storage publication trend

The graph below shows the total number of articles in carbon nanotube-graphene composite materials for energy storage across all publications each year (not limited to Nature Index journals).

Technical terms

Carbon nanotube (CNT): Cylindrical nanostructure of sp²-bonded carbon atoms, offering high conductivity and mechanical strength.

Graphene: Single layer of sp²-bonded carbon atoms arranged in a hexagonal lattice, known for exceptional electrical and thermal properties.

Composite material: A material made by combining two or more distinct phases to achieve synergistic properties not present in individual components.

Specific capacitance: The capacitance per unit mass of an electrode material, indicating its charge-storage capacity.

Heteroatom doping: Introduction of non-carbon atoms (e.g. nitrogen) into the carbon lattice to modify electronic structure and surface chemistry.

References

1. Graphene/Reduced Graphene Oxide-Carbon Nanotubes Composite Electrodes: From Capacitive to Battery-Type Behaviour. Nanomaterials (2021).
2. Optimally conductive networks in randomly dispersed CNT:graphene hybrids. Scientific Reports (2015).
3. Porous carbon nanotube/graphene composites for high-performance supercapacitors. Chemical Physics Letters (2018).
4. One-Step Chemical Vapor Deposition Synthesis of 3D N-doped Carbon Nanotube/N-doped Graphene Hybrid Material on Nickel Foam. Nanomaterials (2018).