With the increasing demand for rapid energy replenishment in electric vehicles and portable electronics, fast-charging lithium-ion batteries require graphite anodes with improved Li ⁺ transport kinetics while maintaining high energy density and long-term stability. Graphite remains the dominant commercial anode material, but its layered structure leads to anisotropic Li ⁺ diffusion, limited edge-plane intercalation sites, concentration polarization, and lithium plating risk under high-rate charging. This mini-review focuses specifically on intrinsic structural design of graphite anodes, rather than electrolyte, artificial SEI, or charging-protocol optimization. Interlayer spacing regulation, porous structure construction, particle size/morphology optimization, and defect/edge-site engineering are summarized within a structure–kinetics–trade-off framework. These strategies can shorten Li ⁺ diffusion pathways, increase effective Li ⁺ entry sites, reduce polarization, and improve high-rate capacity utilization. However, they may also increase specific surface area, reduce initial Coulombic efficiency, decrease compaction density, and impair structural stability. Finally, practical evaluation criteria, including full-cell validation, high areal loading, high compaction density, limited lithium inventory, and lithium plating diagnosis, are discussed to guide future intrinsic graphite design for practical fast-charging batteries.

MXenes have emerged as promising building blocks for micro/nanofluidic transport interfaces because of their lamellar architecture, hydrophilic surface terminations, solution processability, and high electrical conductivity. Unlike conventional porous membranes, stacked MXene nanosheets can form slit-like nanochannels that confine water and ions within angstrom-to nanometer-scale spaces. Recent advances show that ion transport in MXene channels is governed not only by interlayer spacing, but also by channel alignment, lateral flake size, defect density, surface terminations, hydration structure, and interlayer chemistry. Ordered nanochannels, biomimetic sub-nanochannels, and directionally functionalized channel entrances have enabled improved ion selectivity and permeability. Meanwhile, confined water and cation intercalation can regulate local transport barriers, swelling behavior, and nanochannel stability. Crosslinked networks, hydrogel pillars, and mixed-dimensional assemblies further improve the mechanical reliability of MXene channels under aqueous conditions. In addition, light-responsive, pH-gated, voltage-gated, and electroconductive MXene membranes highlight the potential of dynamic ion transport and flow-responsive interfaces. This mini review summarizes recent progress in MXene-enabled micro/nanofluidic transport interfaces, emphasizing structure–transport–stability–response relationships and future opportunities for MEMS-compatible and device-oriented fluidic systems.

This work characterizes oil film evolution and predicts the hydrostatic-to-hydrodynamic dominance transition in low-speed heavy-duty journal bearings under starved lubrication induced by insufficient inlet pressure, accounting for the thermo-viscous coupling effect. A thermo-viscous coupling model (TVCM) based on the Vogel equation is established and compared with the conventional constant viscosity model (CVM). Analyses are conducted with VG460, VG680, and VG1000 lubricants at rotational speeds of 10–50 rpm. Results show that the CVM systematically overestimates temperature rise and effective viscosity by neglecting the negative feedback among temperature rise, viscosity attenuation, and reduced heat generation, with deviations increasing with rotational speed and lubricant viscosity. Under insufficient oil supply, load-carrying capacity rises rapidly then stabilizes, reflecting the hydrostatic-to-hydrodynamic dominance transition. In the hydrodynamic-dominated stage, a dominance shift between hydrodynamic enhancement and thermal softening is identified: the peak load point marks the switching of dominant factors, and the corresponding critical speed decreases with rising lubricant viscosity. This transition is accompanied by a failure mode shift from global oil film breakdown to localized high-temperature adhesive wear and fatigue spalling. These findings provide a theoretical basis for formulating emergency speed limits and safe operation strategies for journal bearings under insufficient oil supply.

MXenes have been widely reviewed as biomedical nanomaterials for sensing, therapy, imaging, drug delivery and tissue engineering. However, most reviews organize MXene studies by biomedical application categories rather than mechanical conditions under which MXene-containing interfaces operate. This leaves an important gap for biomechanical engineering: how MXene-based soft interfaces maintain signal transduction, transport and biological contact when bent, stretched, compressed, hydrated or attached to moving tissues. This mini review addresses that gap by evaluating MXenes as biomechanical interface materials rather than isolated conductive nanofillers or biomedical additives. The rapid growth of MXene-based soft sensors, bioelectronic devices and tissue-contacting systems highlights the need to assess whether these materials can meet translational requirements for stable, deformable, reproducible and biologically compatible interfaces. The review is structured around systems in which mechanical deformation, hydrated transport, electron–ion conduction and biological contact directly affect device function, with representative examples including wearable deformation sensors, electronic skins, hydrogel electrodes, deformable biosensors, wound-contact interfaces and regenerative scaffolds. Applications dominated by drug delivery, cancer therapy, bioimaging, implant coatings or static antibacterial activity are not comprehensively reviewed unless they clarify deformation-dependent transport, tissue contact or interface reliability. We critically compare how surface terminations, oxidation state, flake size, percolation networks, polymer bonding, swelling, modulus matching and biological boundary conditions regulate biomechanical functions. Key challenges include aqueous instability, storage-related degradation, calibration drift, motion artifacts, fatigue, sterilization tolerance and incomplete biological testing. We propose a four-layer interface framework and validation priorities that pair biomechanical testing with cytotoxicity, irritation, inflammatory response and reproducibility assessment.

MXenes are commonly described by the compact formula M _n+1 X _n T _x , yet this notation hides the variables that most strongly determine their behavior: precursor ordering, extraction pathway, vacancies, termination identity and distribution, interlayer ions and water, stacking, and transformation history. This mini review develops a solid-state chemistry framework in which MXenes are treated as chemically programmable metastable solids. The central argument is that synthesis does not simply reveal a pre-existing two-dimensional carbide or nitride sheet; it drives the material along a coupled reaction coordinate that creates a history-dependent lattice, surface, and interlayer state. We connect precursor crystal chemistry to selective extraction, show why terminations and defects must be considered together, interpret intercalation as a structural component of the three-dimensional stacked solid, and examine oxidation and thermal conversion as mechanistic probes of metastability. Recent operando, spectroscopic, computational, and synthesis studies are integrated to identify transferable structure-property relations. We finally propose a minimum state descriptor and experimental priorities for converting empirical recipes into predictive synthesis. This perspective places MXenes squarely within solid-state chemistry and clarifies why nominally identical compositions can display divergent conductivity, mechanics, ion storage, and reactivity.

Mechanical components such as bearings, gears, marine shafts, engine-related parts, and aluminum-alloy structures are frequently subjected to coupled wear, corrosion, humidity variation, temperature cycling, and interfacial degradation during service. MXene-dominant and MXene-containing protective coating systems have recently emerged as promising surface-engineering platforms because MXene nanosheets provide two-dimensional layered structures, tunable surface terminations, high aspect ratios, and solution processability that can contribute to low-shear sliding, tribofilm formation, tortuous diffusion pathways, crack deflection, and interfacial modification. This mini review discusses these protective coating systems from a service-oriented perspective, with particular emphasis on architecture design, coupled wear–corrosion protection, environmental stability, and interfacial durability. Recent progress in multilayer, orientation-controlled, polymer-composite, hybrid, environmentally resistant, and smart/self-healing MXene coating architectures is summarized. The main protective mechanisms are analyzed, including layer sliding, tribochemical reorganization, transfer-film formation, maze effects, defect filling, inhibitor release, crack deflection, and coating/substrate adhesion enhancement. Current challenges are also highlighted, including MXene oxidation, restacking, aggregation, coating cracking, delamination, and insufficient validation under realistic coupled service conditions. Future research should move from material-level coating demonstrations toward service-relevant and ultimately service-validated MXene coating systems for bearings, gears, marine shafts, aluminum-alloy structures, and other mechanically loaded components.