Interface Science Innovation: The Strategic Value and Development Trends of Compatibilizers in the New Energy Vehicle Field

Driven by the dual goals of "dual-carbon" targets and high-end manufacturing upgrades, compatibilizers, acting as "invisible architects" in polymer material interface design, are undergoing a strategic transformation from traditional additives to "chip-level" functional materials. As a key breakthrough point in materials science, compatibilizers play an irreplaceable role in the new energy vehicle field. By precisely regulating the interface bonding between different materials, they address core interface issues in battery material systems, lightweight structural components, and thermal management systems, providing solid technical support for the high-quality development of the new energy vehicle industry.

I. The Interface Regulation Role of Compatibilizers in Battery Material Systems

The challenges and breakthroughs in interface engineering for solid-state batteries represent the forefront of current compatibilizer technology application. Although solid-state batteries offer advantages like high energy density and safety, issues such as poor electrode/electrolyte interface contact, side reactions, and poor mechanical stability severely constrain their commercialization. The solid-solid contact between traditional solid electrolytes and electrode materials lacks the wetting ability of liquid electrolytes, leading to small interface contact area and high resistance. Research shows that when garnet-type solid electrolyte LLZO contacts air, Li₂CO₃ forms on its surface, causing the contact angle between LLZO and lithium metal to significantly exceed 90°, drastically increasing interface resistance.

Compatibilizer technology addresses these interface challenges through the following pathways:

1. Interface Chemical Bonding Technology: A team from the Institute of Metal Research, Chinese Academy of Sciences, innovatively integrated ionic conduction and storage functions in a polymer electrolyte system. By introducing functional groups onto electrode material surfaces via covalent bonds, which react with terminal hydroxyl groups in the solid electrolyte, a covalently bonded electrode-electrolyte interface was constructed. This technology achieved an ionic conductivity of 1.0×10⁻⁴ S/cm for the P(EO₂-S₃) polymer electrolyte at 50°C, increasing cathode energy density by 86%.

2. Dynamic Interface Repair Mechanism: Addressing the pain point of interface degradation during solid-state battery cycling, researchers developed a "dual-ion conductor dynamic interface repair" technology. By introducing functional ions into the interface region, a self-healing-like effect is achieved, effectively mitigating interface contact degradation and significantly improving battery stability under high-rate cycling. This breakthrough enables solid-state batteries to achieve over 2200 stable cycles at a 2C charge-discharge rate with a capacity retention rate exceeding 80%.

3. Composite Electrolyte Interface Optimization: Addressing the incompatibility between sulfide electrolytes and oxide cathodes, compatibilizer technology successfully developed composite electrolyte interface solutions. For example, combining polymer matrices with inorganic electrolyte fillers and using interfacial compatibilizers achieves synergistic effects, maintaining the high ionic conductivity of inorganic electrolytes while inheriting the flexibility of polymers. Experiments show that adding 40 wt% LPSCl filler to a PEO-LiTFSI matrix can increase ionic conductivity from 0.84 mS/cm to 3.6 mS/cm, significantly improving the cycling performance of solid-state batteries.

Compatibilizers also play a crucial role in traditional liquid batteries. For instance, in ceramic coating modification for lithium battery separators, introducing specific compatibilizers can simultaneously improve ceramic particle dispersion, interface bonding strength, and thermal stability, effectively preventing short circuits and enhancing battery safety. Applications of compatibilizers in cathode material coating, anode material surface modification, and electrolyte-electrode interface optimization provide important technical support for the continuous performance improvement of liquid batteries.

II. The Synergistic Enhancement Effect of Compatibilizers in Lightweight Materials

Vehicle lightweighting is an inevitable choice for new energy vehicle development, and compatibility issues within lightweight material systems have become a key bottleneck restricting their application. Compatibilizer technology can effectively solve interface bonding problems between different materials, enhancing the comprehensive performance of composites. Taking carbon fiber/polymer composites as an example, their interface bonding strength directly affects the material's mechanical properties. Research shows that the synergistic application of carbon fiber surface treatment and compatibilizer technology can increase the flexural modulus of carbon fiber/epoxy resin composites to over 4500 MPa, significantly outperforming untreated samples.

The application of compatibilizers in lightweight materials is mainly reflected in the following aspects:

1. Carbon Fiber Composite Interface Modification: Addressing the chemical inertness of carbon fiber surfaces, researchers have developed diversified interface modification technology systems. Vibration plasma协同 treatment technology achieves uniform loosening and surface etching of carbon fiber bundles, creating favorable conditions for resin impregnation. Simultaneously, chemical grafting techniques (e.g., maleic anhydride grafting) introduce active functional groups onto the fiber surface, forming chemical bonds with the resin, significantly improving interface bonding strength. Research from Beihang University indicates that optimizing monomer ratios can achieve an EPDM-based coupling agent grafting rate of 35.51%. Adding 7 wt% to a SiO₂/EPDM system increased tensile strength by 42.3% and significantly improved filler dispersion.

2. Magnesium-Based Composite Interface Enhancement: Although magnesium alloys possess excellent lightweight characteristics, insufficient interface bonding strength between them and reinforcements limits their mechanical properties. Compatibilizer technology addresses the chemical bonding issue between reinforcements and the magnesium matrix through surface treatments (e.g., oxidation, plasma) and interface compatibilizer optimization. For example, chemically grafting polar groups onto carbon fiber surfaces and then connecting them via compatibilizers can significantly improve the impact resistance and fatigue life of magnesium-based composites. Currently, magnesium-based composites are widely used in key new energy vehicle components like battery casings and motor insulation materials, significantly reducing overall vehicle weight.

3. Nanofiller Enhanced Compatibility: Nanofillers like nano-silica and carbon nanotubes have high surface energy and tend to agglomerate, limiting their dispersion and performance in polymer matrices. Compatibilizer technology enables uniform dispersion of nanofillers in polymer matrices through surface modification and dispersion promotion, significantly enhancing the composite's mechanical and thermal conductivity properties. For example, the synergistic application of carboxylated carbon nanotubes and compatibilizers can construct a nano-network structure in the interface region, optimizing stress transfer paths, increasing the elongation at break of carbon fiber-reinforced PEEK composites by over 100 times.

4. Recycled Plastic Regeneration Interface Optimization: Faced with the recycling needs of components like new energy vehicle battery packs, compatibilizer technology demonstrates unique value in the field of recycled plastic regeneration. By improving the interface bonding of waste plastic blend systems using compatibilizers, the tensile strength of HDPE/PP recycled materials can be restored to over 85% of that of virgin materials, meeting the stringent performance requirements for recycled materials in new energy vehicles. This technology not only reduces material costs but also aligns with circular economy and sustainable development requirements.

In the engineering application of lightweight materials, compatibilizer technology has evolved from traditional "general-purpose" types toward "customized" and "multifunctional" directions. Developing specialized compatibilizers for different application scenarios and material systems, while integrating multiple functions like toughening, flame retardancy, and anti-aging, meets the comprehensive performance requirements for lightweight materials in new energy vehicles.

III. The Interface Enhancement Value of Compatibilizers in Thermal Management Systems

Battery thermal management is a core link ensuring the safe operation of new energy vehicles, its performance directly affecting battery life and vehicle range. The application of compatibilizer technology in battery thermal management systems is mainly reflected in the optimization of interface properties for thermal conductive materials, phase change materials, and thermal interface materials.

1. Thermal Conductive Silicone and Composite Interface Optimization: PI film composite thermal conductive silicone is a widely used heat dissipation material in new energy vehicle battery packs, motors, and other components. Compatibilizer technology improves the interface compatibility between fillers (e.g., boron nitride) and the silicone rubber matrix, increasing thermal conductivity from 0.8-2.0 W/m·K for traditional materials to over 8.0 W/m·K, significantly enhancing heat transfer efficiency. Simultaneously, compatibilizers impart good flexibility to the material, allowing it to adapt to components of various shapes and effectively buffer stress from thermal expansion and contraction, providing dual protection for the battery management system.

2. Phase Change Material Shape Stability Improvement: Phase Change Materials (PCM) are favored by researchers for their simple structure, no additional energy consumption, and fast temperature response. However, inherent properties like easy leakage and low thermal conductivity constrain their application in battery thermal management systems. Compatibilizer technology significantly improves the shape stability of PCM through surface modification and interface optimization. For example, using perfluoropolyether (PFPE) to surface-modify boron nitride and then filling it into silicone rubber can prepare shape-stable phase change composites (PCC) with excellent thermal conductivity, effectively reducing the temperature difference within a battery pack to within ±2°C, meeting the stringent requirements for thermal management in new energy vehicles.

3. Boron Nitride Nanotube (BNNT) Interface Modification: BNNTs, with their excellent properties such as a Young's modulus of 1.18 TPa, high thermal conductivity of 350 W·m⁻¹·K⁻¹, and stable bandgap of 5.5 eV, have become highly promising thermal conductive fillers in battery thermal management systems. However, the chemical inertness of BNNTs leads to insufficient interface bonding force with polymer matrices. Compatibilizer technology effectively improves the interface compatibility between BNNTs and matrix materials through a combination of non-covalent modification (e.g., π-π interaction, electrostatic adsorption) and covalent grafting. In specific applications, when compounding BNNTs with silicone rubber, compatibilizers (e.g., PFPE) are needed to reduce surface energy, achieve uniform filler dispersion, reach a thermal conductivity of up to 2400 W/m·K, and maintain stable performance across a wide temperature range from -60°C to 280°C.

4. Multifunctional Integration of Thermal Management Materials: As performance requirements for thermal management systems in new energy vehicles continue to increase, compatibilizer technology is driving thermal management materials toward multifunctional integration. For example, developing thermal management materials that simultaneously possess thermal conductivity, insulation, flame retardancy, and self-healing functions. By regulating the interface compatibility between different functional components via compatibilizers, synergistic performance enhancement is achieved. This type of multifunctional integrated thermal management material not only effectively manages battery temperature but also provides additional protection under extreme conditions, significantly improving the safety and reliability of battery systems.

The application of compatibilizers in thermal management systems has evolved from simple interface bonding toward interface functionalization, achieving performance breakthroughs in thermal management materials through interface design, providing important safeguards for the safe operation of new energy vehicle batteries.

IV. Future Development Trends and Innovation Directions for Compatibilizer Technology

With the continuous development of new energy vehicle technology and increasing material demands, compatibilizer technology will also usher in a series of innovative breakthroughs and development trends.

1. Refinement and Intelligence of Interface Engineering: Future compatibilizer technology will develop from macro-scale interface optimization toward molecular-scale interface regulation, achieving precise control of interface structure and performance. AI algorithms and computational simulation technologies will be deeply integrated into the compatibilizer design and development process, accelerating the development and optimization of new compatibilizers by predicting interface interactions and performance relationships. Companies like Solvay have adopted AI algorithms to optimize molecular structure design, significantly shortening new product development cycles while using IoT technology for real-time production process monitoring to enhance quality stability.

2. Development of Multifunctional Composite Compatibilizers: Addressing the comprehensive performance demands of new energy vehicles for materials, compatibilizer technology will develop toward multifunctional composite directions. Developing composite compatibilizers with combined functions like compatibilization, flame retardancy, thermal conductivity, and antistatic properties can reduce downstream customers' additive usage and lower overall costs. For example, targeting lithium battery separator (ceramic coating) needs, companies have launched products integrating ceramic dispersion, interface bonding, and thermal stabilization functions, significantly improving separator safety and cycle life.

3. Industrialization of Green and Low-Carbon Compatibilizers: Driven by "dual-carbon" targets and global environmental regulations, green and low-carbon compatibilizers will become an important development direction for the industry. Bio-based compatibilizers (e.g., PLA-based, Polyhydroxyalkanoate (PHA)-based) and CO₂-based compatibilizers (e.g., CO₂ polycarbonate developed by Wanhua Chemical) will accelerate their industrialization, meeting environmental regulations and reducing carbon emissions. Sinopec's construction of the world's largest polylactic acid production base provides a stable raw material supply for bio-based compatibilizers, promoting their small-scale application in fields like food packaging and disposable tableware. Simultaneously, compatibilizer technology for recycled plastics is continuously developing, making recycled material performance virgin material levels by optimizing interface compatibility.

4. Application of Temperature-Sensitive Compatibilizers in Smart Materials: The application of temperature-sensitive compatibilizers (e.g., PNIPAM graft copolymers) in 4D printing materials is on the verge of commercialization. These compatibilizers can achieve programmable shape deformation of materials based on temperature changes, providing intelligent, adaptive structural components for new energy vehicles. In the future, more intelligent responsive compatibilizers will be developed to meet the needs of different application scenarios, such as self-healing materials and smart sensing materials, the compatibilizer industry toward intelligent development.

5. Engineering Application and Standardization Construction: With the continuous development of compatibilizer technology, its engineering application and standardization construction will also become important trends. For emerging application fields like solid-state batteries, compatibilizers need to adapt to new manufacturing processes like roll-to-roll coating to achieve stable control of interface performance. Simultaneously, the standard system for compatibilizers is continuously improving. For example, the "All-Solid-State Battery Judgment Method" (March 2025) requires interface impedance ≤50 Ω·cm², providing a unified standard for compatibilizer performance evaluation and quality control.

6. Industry-University-Research Collaborative Innovation and Technology Transfer: The innovative development of compatibilizer technology will increasingly rely on industry-university-research collaboration. Universities and research institutions will provide cutting-edge technology and theoretical support, while enterprises will be responsible for technology transfer and industrial application. For example, the polylactic acid-based compatibilizer developed by the Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, has achieved small-scale application in fields like food packaging and disposable tableware, while the Shanghai Research Institute of Chemical Industry leads 80% of national-level projects, mastering core technologies like nano-silver paste. This collaborative innovation model will accelerate breakthroughs and applications in compatibilizer technology.

V. Conclusion and Outlook

As "invisible architects" of material interface design, compatibilizers are playing an increasingly important strategic role in the new energy vehicle field. From interface regulation in battery material systems to performance optimization of lightweight structural components, from functional enhancement of thermal management systems to material recycling, the innovation and application of compatibilizer technology are continuously driving the high-quality development of the new energy vehicle industry.

The future development of compatibilizer technology will focus on directions such as refinement of interface engineering, functional, green and low-carbon, and intelligent responsiveness. Through the of technological innovation and engineering application, it will solve interface challenges in new energy vehicle material systems, providing solid technical support for the sustainable development of the new energy vehicle industry.

With continuous national policy support and rapid market demand growth, the compatibilizer industry will usher in new development opportunities. The "2025 Key Directions for Advanced Materials" lists compatibilizers as key new materials, requiring the localization rate of 5G high-frequency compatibilizers to exceed 90% by 2026, providing clear direction and policy guarantees for the compatibilizer industry's development. Simultaneously, local innovative policies like Shenzhen's "Green Factory Credit System" also provide economic incentives and market space for companies to develop green and low-carbon compatibilizers.

In this context, compatibilizer enterprises should increase R&D investment, focus on the interface demands of strategic emerging industries like new energy vehicles, develop high-performance, multifunctional, green and low-carbon compatibilizer products, and enhance core competitiveness and market influence. They should also strengthen industry-university-research collaboration, promote the transfer and application of cutting-edge technologies, and provide powerful technical support for the sustainable development of the new energy vehicle industry.

The innovative development of compatibilizer technology is not only related to the progress of materials science but will also directly impact the technological pathways and industrial landscape of strategic emerging industries like new energy vehicles. In the future, with the continuous breakthroughs and expanded applications of compatibilizer technology, material interface design will become more precise and efficient, injecting new momentum and providing new support for the high-quality development of the new energy vehicle industry.