Authors: Sara Mohseni Taromsari | Meysam Salari | Lih-Wen Hwang | Hani E. Naguib
Source: ECS Meeting Abstracts (article, 2025-07-11)
Field: Materials Science — Materials Chemistry

Freeze-Cast MXene–Graphene Nanoribbon Architectures for High-Performance Lithium-Ion Batteries As the world shifts toward clean energy systems and electric transportation, the need for advanced, long-lasting lithium-ion batteries (LIBs) becomes increasingly urgent. Applications from grid-scale energy storage to rapidly charging electric vehicles place unprecedented demands on battery electrodes—requiring higher energy densities, faster ion transport, and robust stability over extended cycling. Among emerging electrode materials, two-dimensional (2D) transition metal carbides and nitrides (MXenes) show particular promise. Ti₃C₂Tₓ MXene, in particular, offers high electrical conductivity, tunable surface chemistry, and layered structures theoretically capable of accommodating abundant lithium-ion storage. However, real-world implementations rarely approach this theoretical potential due to persistent challenges such as sheet restacking, restricted electrolyte penetration, and interfacial instabilities. Additionally, the pervasive use of polymeric binders often impedes electron transfer, reduces accessible active sites, and contributes to long-term degradation. To tackle these issues, we introduce a comprehensive electrode engineering strategy that leverages the synergy between Ti₃C₂Tₓ MXene and graphene nanoribbons (GnRs). Instead of relying on conventional binders that insulate and obstruct ion and electron movement, we incorporate GnRs to mechanically stabilize the electrode and maintain electrically conductive pathways. This approach preserves the inherent advantages of the MXene layers—expansive surface area, high conductivity, and adjustable surface groups—while ensuring open channels for ion transport and electron conduction. By protecting active sites from blockage, we enhance the utilization of the MXene’s theoretical capacity. A key element of this framework is the use of freeze-casting to shape the MXene–GnR composite into a three-dimensional scaffold. During freezing, ice crystals impose a vertical order on the dispersed flakes and ribbons. After the ice is removed by sublimation, what remains is a porous, aerogel-like electrode with aligned channels. These ordered pores promote uniform Li-ion distribution, reduce tortuosity, and prevent the restacking of MXene flakes that can limit capacity. The resultant architecture not only enhances ion and electrolyte transport but also maintains mechanical integrity during repeated lithiation and delithiation cycles, mitigating the risk of structural collapse and improving long-term stability. This strategy also tackles the isiue of unwanted chemical reactions as we employ targeted post-processing treatments. Gentle thermal annealing and chemical reduction steps remove oxygen-containing groups from the GnRs, thereby improving their conductivity and ensuring stronger electronic coupling with the MXene flakes. Simultaneously, refining the MXene surface terminations reduces detrimental reactions with the electrolyte, stabilizing the electrode–electrolyte interface. These combined adjustments enable a more stable electrochemical environment, increasing the reversibility of lithium storage and preserving capacity over prolonged cycling. The electrochemical performance of our Ti₃C₂Tₓ@GnR electrode system validates the effectiveness of this integrated approach. Freed from insulating binders, the electrode demonstrates significantly enhanced capacity and rate capability. At a moderate current density of 0.2 A g⁻¹, the electrode achieves a specific capacity of 389 mAh g⁻¹ during charge and 401 mAh g⁻¹ during discharge. Even more impressively, it retains approximately 92% of its initial capacity over extended cycling, reflecting robust structural and interfacial stability. High-rate performance is equally encouraging: at a demanding current density of 5 A g⁻¹, the electrode still delivers a capacity of 220 mAh g⁻¹, showcasing rapid ionic transport and excellent reversibility under fast-charging conditions. These results mark a notable shift from incremental improvements to a more holistic re-envisioning of electrode design. By unifying material selection, structural engineering, and interfacial tuning, we harmonize multiple performance attributes—capacity, rate capability, and long-term stability—into a single, cohesive solution. Beyond just laboratory demonstrations, this approach aligns with industrial considerations. The freeze-casting process is solution-based, scalable, and does not necessitate complex or vacuum-intensive steps. The absence of polymer binders, coupled with the widespread availability of carbon nanostructures, reduces barriers to mass production, making this concept commercially appealing. More broadly, the principles outlined here—integrating 2D materials with tailored additives, employing ice-templating to achieve an ideal porous architecture, and using post-treatments to fine-tune chemistry—hold potential for a variety of next-generation electrode systems. Graphene ; Lithium (medication) ; Materials science ; Nanotechnology ; Ion ; Optoelectronics ; Engineering physics ; Chemistry ; Engineering ; Psychology MXene and MAX Phase Materials ; Graphene research and applications ; Advancements in Battery Materials