The research team at Virginia Tech recently published a significant achievement in ACS Applied Materials & Interfaces, demonstrating that a Molecular Ion Composite (MIC) polymer electrolyte developed by the team, through the introduction of CHEMFISH's functional additive LiDFBOP (lithium difluorobis(oxalato)phosphate), has successfully addressed the challenge of electrode-electrolyte interface stability in high-voltage lithium batteries. This breakthrough paves a new path for the commercial application of next-generation high-energy-density solid-state batteries.

https://pubs.acs.org/doi/10.1021/acsami.5c04566

Technical Bottleneck of High-Voltage Batteries: Challenges in Interface Stability
As the demand for high-energy-density batteries in new energy vehicles and energy storage technologies grows, the combination of high-voltage layered oxide cathodes (such as NMC811) and metallic lithium anodes has become a research hotspot. However, traditional polymer electrolytes are prone to decomposition under high voltage, leading to interfacial side reactions and lithium dendrite growth, which severely affect the cycle life and safety of batteries. The MIC electrolyte system proposed by Professor Feng Lin's team from the Department of Chemistry at Virginia Tech constructs an integrated electrolyte membrane with excellent mechanical strength and electrochemical stability through the synergistic effect of rigid rod-shaped ionomer PBDT, ionic liquids, lithium salts, and functional additives.

CHEMFISH LiDFBOP: The "Core Engine" for Interface Optimization
In this study, the LiDFBOP additive provided by CHEMFISH played a key role:

• Interfacial Passivation: LiDFBOP decomposes on the electrode surface to form a stable passivation layer rich in Li₃N and sulfur-containing compounds, effectively inhibiting the oxidative degradation of the electrolyte under high voltage. X-ray photoelectron spectroscopy (XPS) analysis shows that after using the gen 2 MIC electrolyte containing LiDFBOP, a uniform protective film forms on the surface of the NMC811 cathode, significantly reducing interfacial impedance.
• Ion Transport Regulation: LiDFBOP, in collaboration with the solvent sulfolane (SL), optimizes the solvation structure in the ionic liquid, enabling the ion conductivity of the gen 2 MIC electrolyte to reach 3.21 mS cm⁻¹ at 60°C, a 31% increase compared to the previous generation system.
• Enhanced Cycling Performance: In an NMC811||Li metal battery, the battery equipped with the gen 2 MIC electrolyte achieves an initial discharge specific capacity of 212 mAh g⁻¹, with a capacity retention rate of 93% after 100 cycles (2.8–4.4 V, C/3, 60°C), far exceeding the system without LiDFBOP addition.

Technical Breakthrough: From Material Design to Performance Leap
The research team constructed the "second-generation MIC (gen 2 MIC)" system through molecular design, with innovations including:

• Multicomponent Synergistic Effect: A self-supporting electrolyte membrane is formed by compounding 7.5% PBDT polymer, 7.5% LiTFSI, 60% ionic liquid Pyr₁₄TFSI, 22.5% sulfolane, and 2.5% LiDFBOP, eliminating the need for additional liquid electrolyte.
• Wide-Temperature Stability: Thermogravimetric analysis (TGA) shows that gen 2 MIC has only a 20% mass loss below 400°C. Combined with the tensile strength of 6.3 MPa and elastic modulus of 450 MPa measured by dynamic mechanical thermal analysis (DMTA), it meets the requirements for actual battery packaging.
• Interfacial Chemical Regulation: Phosphorus-based compounds decomposed from LiDFBOP work in tandem with Li₃N decomposed from TFSI⁻ to form ion-conducting channels while inhibiting lithium dendrite growth, enabling a Li||Li symmetric battery to stably cycle for 500 hours at a current density of 0.3 mA cm⁻².

Industrial Prospects: Advancing the Commercialization Process of Solid-State Batteries
This research not only provides a new electrolyte solution for high-voltage lithium batteries but also highlights the critical value of functional additives in electrochemical interface engineering. As a high-purity functional salt (purity ≥99.9%, water content ≤500 ppm), CHEMFISH's LiDFBOP offers standardized raw material support for electrolyte material design through its controllable decomposition behavior and interfacial modification capabilities.

Professor Feng Lin stated, "The advantage of the MIC electrolyte system lies in its customizable molecular design framework, and CHEMFISH's high-performance additives provide key support for achieving a balance between interface stability and ion conductivity. This technology is expected to be applied in high-energy-density batteries for electric vehicles, aerospace, and other fields."

Currently, the research team has applied for a patent related to the technology (application number 63/734,312) and plans to collaborate with battery companies to advance pilot-scale testing. With the improvement of the solid-state battery industry chain, core materials from suppliers like CHEMFISH will play an increasingly important role in breakthroughs in next-generation battery technologies.