Lithium Battery Materials
Specialty additives across separator, cathode, electrolyte, TIM and pack
SEMITECH supplies fumed metal oxides and silicone-based additives for lithium-ion and semi-solid battery manufacturers — engineered for high-Ni cathode stability, separator thermal integrity, electrolyte gelation, and pack thermal management.
FAMILIES 5 SOLUTIONS 5 UPDATED Apr 2026
Contents
SEMITECH at a glance
Material families5
Battery solutions5
Custom gradesYes
Sample availableYes
Why specialty additives matter for Li-ion
As cell energy density climbs and pack architectures move toward cell-to-pack and cell-to-chassis designs, specialty inorganic and silicone additives have moved from formulation tweaks to structural enablers.
Three pressures converge on every modern lithium battery. Thermal runaway prevention demands ceramic-coated separators and flame-retardant pack materials. Energy density pushes the industry toward high-nickel cathodes, which bring surface instability and gas evolution challenges. Cycle life hinges on SEI integrity and electrode-electrolyte interfaces. SEMITECH’s portfolio of fumed metal oxides and silicone chemistry addresses each of these pressures with field-proven materials.
Battery anatomy and material map
SEMITECH materials sit at five critical insertion points across the cell-to-pack architecture:
Cell-level — separator coating (fumed alumina, fumed silica), cathode surface coating (fumed alumina), electrolyte gelation (fumed silica).
Pack-level — thermal interface materials (vinyl + hydrogen silicone fluid), encapsulation and ESS anti-corrosion (MESIL OH polymer, anti-corrosive pigment).
Five solution areas
Fumed alumina and fumed silica raise separator thermal stability above 180 °C, suppress shrinkage, and improve electrolyte wettability for high-energy NMC and NCA cells.
Nano-grade fumed alumina coating suppresses cation mixing on Ni-rich cathodes, reduces gas evolution during cycling, and extends calendar life under elevated temperatures.
Hydrophilic and hydrophobic fumed silica grades enable gel polymer electrolytes (GPE), reduce free liquid leakage, and serve as inorganic fillers for semi-solid formulations.
Vinyl-terminated and hydrogen-functional silicone fluids form the base chemistry for two-component addition-cure TIMs, gap fillers, and thermal pads bridging cells to cooling plates.
MESIL OH polymer is the silanol-terminated PDMS base for one-component RTV potting compounds and module sealants. Anti-corrosive pigment supports outdoor energy storage container coatings.
Battery manufacturing process flow
Where SEMITECH materials enter the cell-to-pack workflow:
- STEP 1Slurry PrepFumed Silica
Cathode and coating slurry rheology and anti-settling.
- STEP 2CoatingFumed Alumina
Separator ceramic layer; high-Ni cathode surface coat.
- STEP 3Cell AssemblyFumed Silica (GPE)
Electrolyte gelation in semi-solid formats.
- STEP 4Module / PackSilicone TIM + RTV
Thermal interface, gap-fill, potting and module sealing.
Selection guide
| Battery Layer | Function | SEMITECH Product | Reference Grade |
|---|---|---|---|
| Separator | Ceramic coating | Fumed Alumina | SEMIAL series |
| Separator | Coating slurry rheology | Fumed Silica | SEMISIL 200 |
| Cathode (high-Ni) | Surface coating | Fumed Alumina (nano) | SEMIAL nano |
| Electrolyte | GPE / semi-solid filler | Fumed Silica | SEMISIL 200 |
| Module TIM | Addition-cure base | Vinyl Silicone Fluid | MESIL VTM |
| Module TIM | Crosslinker | Hydrogen Silicone Fluid | MESIL HSF |
| Pack | RTV potting / sealing | MESIL OH Polymer | MESIL-OH |
| ESS Container | Outdoor anti-corrosion | Anti-Corrosive Pigment | SEMICOR series |
FAQ
+Why use fumed alumina rather than boehmite for separator coating?
Both work. Fumed alumina (γ-Al₂O₃) offers higher surface area and stronger ion adsorption sites; boehmite (γ-AlOOH) is denser and lower cost. For high-end NMC811 and beyond, fumed alumina’s higher purity and finer particle size improve dimensional stability above 180 °C.
+Can fumed silica replace PVDF in electrolyte gelation?
Not directly. PVDF acts as the polymer matrix while fumed silica acts as the inorganic gelling agent — they are complementary. Typical GPE formulations combine 1–3 wt % fumed silica with 5–10 wt % PVDF-HFP for synergistic gelation.
+How is TIM viscosity selected for battery modules?
Gap-fillers between cells and cooling plates typically target 50,000–500,000 cP for dispense-grade TIMs. Lower viscosity enables fine dispense for narrow gaps; higher viscosity improves hold on vertical surfaces. SEMITECH offers vinyl and hydrogen silicone bases at multiple viscosity grades for formulators to dial in.
+Are SEMITECH silicones compatible with EC/DEC/EMC electrolytes?
Cured silicone elastomers are chemically inert toward standard carbonate electrolytes and lithium hexafluorophosphate (LiPF₆) at typical operating temperatures (< 60 °C). For prolonged contact above 80 °C, our team recommends platinum-cured systems with low-extractable formulations — request the compatibility datasheet.
+What loading of fumed silica is typical in gel polymer electrolyte?
Most published GPE formulations use 1–5 wt % fumed silica relative to electrolyte, with 2–3 wt % being a common starting point. Hydrophobic-treated grades (HMDS or PDMS surface modification) improve compatibility with carbonate solvents.
+Does SEMITECH support semi-solid battery R&D?
Yes. We provide hydrophilic and surface-modified hydrophobic fumed silica grades, plus fumed alumina nano-grades, for solid-state and semi-solid pilot lines. Our technical team assists with surface chemistry selection, compatibility testing, and small-batch custom modification.
+What grades of fumed alumina suit high-Ni cathodes?
For NMC811 and NCA surface coating, target nano-grade fumed alumina with primary particle size 13–20 nm and BET surface area > 100 m²/g. Coating thickness in the 2–5 nm range typically suppresses cation mixing without sacrificing rate capability.
+Do you offer custom samples for new formulations?
Yes. Standard grades ship in 100 g, 1 kg, and 25 kg trial sizes. Surface-modified or particle-size-targeted custom grades require an NDA and 4–8 week pilot lead time. Contact our applications team to scope a sample protocol.
Detailed datasheets, chemical compatibility data, and certificate of analysis available upon request. Last updated April 2026.