Two-Dimensional Transition Metal Carbides for Energy Storage Applications

Two-dimensional transition metal carbides, commonly known as MXenes, have emerged as a versatile class of layered materials combining metallic conductivity, mechanical flexibility and rich surface chemistry. Derived by selective etching of layered precursors, these materials exhibit single- to few-atom-thick sheets of early transition metals bonded to carbon or nitrogen. Their high electrical conductivity, hydrophilicity and tunable surface terminations facilitate rapid charge transport and redox activity, making them promising for both battery and supercapacitor technologies. In electrochemical cells, ion storage occurs through a mixture of double-layer formation, pseudocapacitive surface reactions and intercalation into the interlayer galleries. The ability to tailor interlayer spacing and functional groups offers control over ion accessibility, rate capability and cycle life. Beyond fundamental electrochemistry, MXenes have been integrated into flexible and printable formats, enabling lightweight, high-power modules suited to portable electronics and grid stabilisation. Challenges remain in stabilising these carbides against oxidation, mitigating restacking of nanosheets and scaling synthesis routes while preserving desired architectures. Nevertheless, ongoing advances in atomic-scale design, surface engineering and composite assembly point to a new generation of energy storage devices that balance energy density, power output and durability on a global scale.

Research from Nature Portfolio

Recent studies have demonstrated that titanium-based MXenes display pronounced pseudocapacitive behaviour when employed as electrodes in sodium-ion hybrid capacitors, delivering high specific capacity and exceptional rate capability through rapid surface redox reactions. Advances in printing technology have yielded additive-free aqueous and organic MXene inks, enabling direct fabrication of micro-supercapacitors on flexible substrates; these devices exhibit volumetric capacitances and energy densities markedly superior to existing printed materials. Further work has shown that controlled de-functionalisation and ion intercalation can be used to tune the electronic conductivity of MXene films; in situ annealing and biasing experiments reveal transitions between metallic and semiconductor-like transport, suggesting routes to optimise charge-transfer kinetics in energy-storage architectures.

Two-Dimensional Transition Metal Carbides for Energy Storage Applications publication trend

The graph below shows the total number of articles in two-dimensional transition metal carbides for energy storage applications across all publications each year (not limited to Nature Index journals).

Technical terms

MXene: Two-dimensional transition metal carbides or nitrides obtained by selective etching of layered precursors, featuring high conductivity and tunable surface chemistry.

Pseudocapacitance: Charge storage mechanism involving fast, reversible surface redox reactions that contribute to capacitance beyond electric double-layer effects.

Surface termination: Functional groups (such as –O, –OH or –F) bonded to the exposed surfaces of MXene sheets, influencing electronic properties and ion affinity.

Volumetric capacitance: Capacitance measured per unit volume of electrode material, reflecting compact energy storage performance.

Intercalation: Insertion of ions between the layers of a host material, enabling reversible energy storage via bulk redox processes.

References

1. Atomic Scale Design of MXenes and Their Parent MaterialsFrom Theoretical and Experimental Perspectives. Chemical Reviews (2023).
2. MXene Enhanced 3D Needled Waste Denim Felt for High-Performance Flexible Supercapacitors. Nano-Micro Letters (2023).
3. Pseudocapacitance of MXene nanosheets for high-power sodium-ion hybrid capacitors. Nature Communications (2015).
4. Ion Intercalation into Two-Dimensional Transition-Metal Carbides: Global Screening for New High-Capacity Battery Materials. Journal of the American Chemical Society (2014).
5. Control of MXenes’ electronic properties through termination and intercalation. Nature Communications (2019).
6. Additive-free MXene inks and direct printing of micro-supercapacitors. Nature Communications (2019).
7. Modified MXene/Holey Graphene Films for Advanced Supercapacitor Electrodes with Superior Energy Storage. Advanced Science (2018).
8. Oxidation stability of Ti3C2Tx MXene nanosheets in solvents and composite films. npj 2D Materials and Applications (2019).