Intrinsic Manipulation of Interfacial Water in Titanium Carbide MXene via Carbon Vacancy Engineering for Superior Pseudocapacitive Storage

Why It Matters

By enhancing internal water interactions without external additives, the study unlocks higher energy and power densities for MXene‑based supercapacitors, accelerating their viability in fast‑charging applications and grid‑scale storage.

Key Takeaways

• Carbon vacancies polarize O‑terminations, boosting H‑bonding with water.
• Ti3C1.7 MXene delivers 348 F g⁻¹ at 5 mV s⁻¹, 47% higher.
• Anodic oxidation raises capacitance to 382 F g⁻¹, retains 45% at 5000 mV s⁻¹.
• Intrinsic interlayer design offers scalable path to high‑power pseudocapacitors.

Pulse Analysis

MXenes have emerged as a leading class of two‑dimensional materials for electrochemical energy storage, thanks to their metallic conductivity and tunable surface terminations. Traditional strategies to boost capacitance rely on intercalating foreign ions or molecules, which can compromise structural stability and introduce processing complexity. The new approach of engineering carbon vacancies directly within the Ti3C2Tx lattice sidesteps these drawbacks, creating a more permanent modification of the electronic environment that enhances the affinity of surface oxygen groups for confined water molecules. This shift from external to intrinsic control marks a conceptual advance in MXene design.

The experimental results underscore the practical impact of this lattice‑level tuning. Polarized oxygen terminations form stronger hydrogen bonds with interlayer water, establishing a stable “active and fixed” architecture that resists thermal degradation. Electrochemical testing shows the Ti3C1.7 variant achieving 348 F g⁻¹ at a moderate scan rate, a 47% improvement over the near‑stoichiometric counterpart. Subsequent anodic oxidation further alleviates ion‑diffusion bottlenecks, pushing capacitance to 382 F g⁻¹ and preserving nearly half of that value even at an aggressive 5000 mV s⁻¹ scan. Compared with conventional MXene electrodes, these figures represent a substantial leap in both energy and power density, positioning the material for high‑rate applications such as electric‑vehicle fast charging and responsive grid buffering.

Beyond the laboratory, the findings have broader commercial implications. The vacancy‑engineered MXene can be synthesized using scalable chemical etching and annealing processes already familiar to the semiconductor and battery industries, reducing barriers to mass production. Moreover, the principle of tailoring interfacial hydrogen‑bond networks could be extended to other layered conductors, opening a new design space for next‑generation supercapacitors. As demand for rapid‑charge, high‑power storage grows, this intrinsic manipulation strategy offers a clear pathway to meet performance targets while maintaining material robustness.