Censil battery separator grade precipitated silica - high purity, optimized porosity & absorption for lithium-ion battery separators and lead-acid AGM batteries. China manufacturer. Free sample.
Specially engineered precipitated silica for lithium-ion battery separators. High purity, optimized porosity, superior ion conductivity and thermal stability.
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Censil is a specialized manufacturer of battery separator grade silica, produced by Longyan Shenghe Chemical Co., Ltd. in Fujian, China. With over 15 years of precipitated silica production expertise, Censil supplies high-purity, low-iron silica specifically engineered for battery separator applications — serving lithium-ion battery ceramic coating manufacturers and PE separator producers for lead-acid batteries worldwide.
Censil battery separator grade silica is the critical functional material that creates the microporous structure in battery separators, enabling controlled electrolyte absorption, ion conductivity, and thermal stability. As a trusted battery separator silica supplier, Censil holds ISO 9001, ISO 14001, FAMI-QS (Certificate No. CNBJ380053-CN), and HALAL certifications, ensuring consistent quality for battery manufacturers across EV, energy storage, and industrial battery markets.
Censil battery separator grade silica is widely used in lithium-ion battery ceramic-coated separators and composite separator manufacturing. As the inorganic functional filler in ceramic coating slurries, Censil silica creates a thermally stable skeleton on PE/PP separator films that prevents thermal shrinkage, enhances electrolyte wettability, and improves resistance to lithium dendrite penetration — critical safety and performance requirements for EV batteries and energy storage systems.
| Performance Parameter | Role of Silica | Result |
|---|---|---|
| Thermal Stability | Inorganic silica skeleton (mp >1600°C) prevents PE/PP shrinkage at high temperatures | Dimensional shrinkage <2% at 150°C vs >10% for pure PE separators |
| Electrolyte Wettability | Abundant surface -OH (silanol) groups attract polar electrolyte components | Rapid wetting, uniform electrolyte distribution, strong liquid uptake |
| Ionic Conductivity | Nanoscale silica forms 3D microporous network with interconnected ion channels | Lower internal resistance, enhanced fast-charging performance |
| Mechanical Strength | Uniformly dispersed silica increases puncture resistance and tensile strength | Protection against lithium dendrite penetration and winding damage |
| Cycle Life | Stable pore structure maintains ion transport over repeated charge-discharge | Extended battery lifespan, consistent capacity retention |
| Safety (Thermal Runaway) | Ceramic coating acts as firewall — does not melt at thermal abuse conditions | Prevents internal short circuits, buys time for BMS response |
The typical manufacturing process for ceramic-coated separators using Censil battery separator grade silica involves:
As a silica for lithium battery separator applications, Censil's controlled particle size distribution (D50 optimized for coating processes) and low metal impurity content ensure consistent coating quality and electrochemical performance in mass production.
In lead-acid battery applications, Censil battery separator grade silica serves as the structural skeleton and pore-forming agent in polyethylene (PE) microporous separators. The silica accounts for approximately 60% of the total separator weight, forming a rigid, acid-resistant network that defines the pore structure through which sulfuric acid electrolyte and ions diffuse between battery plates.
| Component | Weight % | Function |
|---|---|---|
| Precipitated Silica (Censil) | 55-65% | Structural skeleton, pore-forming agent — defines pore size and porosity |
| UHMW-PE | 30-40% | Matrix binder, acid-resistant polymer phase |
| Process Oil | 5-15% | Plasticizer for extrusion, extracted to create pores |
| Additives | <1% | Antioxidants, carbon black, processing aids |
| Battery Type | Application | Key Requirement |
|---|---|---|
| SLI (Starting, Lighting, Ignition) | Automotive starter batteries | Low electrical resistance for high cranking current |
| Deep-Cycle Industrial | Forklift, UPS, stationary storage | Long cycle life, oxidation resistance |
| VRLA (Valve-Regulated Lead-Acid) | AGM batteries, telecom backup | High porosity for electrolyte retention in AGM design |
| Start-Stop (EFB/AGM) | Modern vehicles with start-stop systems | Enhanced cycling durability, fast charge acceptance |
The porosity of the separator is the key performance index — determined by the pore characteristics of the filler silica. Censil battery separator grade silica is engineered with a controlled porous structure, appropriate specific surface area (BET 100-150 m²/g), and uniform particle size distribution to create separators with optimal pore diameter (0.1-1.0 µm), low electrical resistance, and excellent acid resistance in 30-40% H₂SO₄ at operating temperatures up to 60°C.
Censil battery separator grade silica is engineered with precise specifications for battery separator manufacturing. The following table details the complete technical parameters.
| Parameter | Unit | Specification | Significance for Battery Performance |
|---|---|---|---|
| Appearance | — | White powder | Visual quality indicator |
| SiO₂ Content (dry basis) | % | ≥98 | High silica purity for chemical stability in battery environment |
| BET Specific Surface Area | m²/g | 100-150 | Optimized for electrolyte absorption without excessive binder demand |
| DBP Absorption | cm³/g | 2.00-3.50 | Controls pore volume and electrolyte retention capacity |
| Particle Size | µm | 60-150 | Determines pore diameter in separator — critical for ion conductivity |
| 45 µm (325 mesh) Residue | % | ≤0.5 | Ensures uniform particle distribution, prevents large pore defects |
| Loss on Drying (105°C, 2h) | % | 4.0-8.0 | Consistent moisture for stable extrusion processing |
| Ignition Loss (1000°C, 2h) | % | ≤7.0 | Indicates surface hydroxyl content — affects silica-PE compatibility |
| pH Value (5% suspension) | — | 5.0-8.0 | Neutral pH prevents acid-base reactions in battery environment |
| Salt as Na₂SO₄ | % | ≤2.5 | Low salt content prevents ionic contamination in battery cells |
| Total Iron (Fe) Content | mg/kg | ≤500 | Critical — iron contamination causes self-discharge and grid corrosion in lead-acid batteries |
Battery separator manufacturers evaluating battery separator grade silica suppliers need consistent quality, controlled purity, and competitive pricing. Below is a comparison showing how Censil positions against typical market alternatives.
| Parameter | Censil Battery Silica | Typical International Brand A | Typical Domestic Brand B |
|---|---|---|---|
| SiO₂ Content | ≥98% | ≥98% | ≥96% |
| BET Surface Area | 100-150 m²/g | 100-150 m²/g | 130-160 m²/g |
| Particle Size | 60-150 µm | 50-120 µm | 80-200 µm |
| Total Iron (Fe) | ≤500 mg/kg | ≤300 mg/kg | ≤800 mg/kg |
| DBP Absorption | 2.00-3.50 cm³/g | 2.0-3.0 cm³/g | 2.5-4.0 cm³/g |
| ISO 9001 / ISO 14001 | ✅ Both | ✅ Both | ✅ ISO 9001 only |
| Cost Index | 100 | 160-200 | 80-110 |
| Lead Time | 2-3 weeks | 6-10 weeks | 1-2 weeks |
| Customization | BET, particle size adjustable | Fixed specs | Limited |
Key Finding: Censil battery separator grade silica matches international brand specifications while offering 40-50% cost savings and significantly shorter lead times. As a China-based battery separator silica manufacturer, Censil provides the quality consistency battery manufacturers require with the pricing advantage of domestic production. For companies seeking an alternative to imported battery grade silica brands, Censil delivers reliable supply with full technical documentation and sample support.
A battery separator is a thin, electrically insulating membrane placed between the positive and negative electrodes. Its function is to prevent electrical short circuits while allowing ionic current flow through the electrolyte. The separator must be:
Silica fulfills all these requirements simultaneously. In PE separators, the silica-PE composite structure creates a controlled microporous network (pore diameter 0.1-1.0 µm, porosity >40%) that enables electrolyte diffusion and ion migration. In ceramic-coated separators, the silica layer provides a thermal barrier that prevents separator collapse during thermal events — a critical safety feature for lithium-ion batteries.
The porosity of the separator is the single most important performance index. Porosity is determined by the pore characteristics of the filler silica — specifically:
Censil battery separator grade silica is engineered with optimized pore characteristics to deliver separators with low electrical resistance, high oxidation resistance, and excellent puncture strength — meeting DIN 40742 and BCI industry standards.
Censil battery separator grade silica is manufactured under internationally recognized quality management systems:
Each production batch undergoes rigorous quality testing including ICP analysis for metal impurities, laser diffraction for particle size distribution, and BET surface area measurement to ensure consistent performance in battery separator manufacturing.
Battery separator grade silica is a specially engineered precipitated silica used as the structural skeleton and pore-forming agent in battery separators. In PE separators for lead-acid batteries, silica accounts for approximately 60% of total separator weight, creating a microporous structure that allows electrolyte diffusion and ion migration while preventing electrical short circuits. For lithium-ion battery ceramic coatings, high-purity silica forms a thermally stable inorganic layer on PE/PP separators, improving thermal runaway resistance and electrolyte wettability.
Censil battery separator grade silica features: SiO₂ ≥98%, BET surface area 100-150 m²/g, DBP absorption 2.00-3.50 cm³/g, particle size 60-150 µm, total iron ≤500 mg/kg, loss on drying ≤8%, and ignition loss ≤7%. The controlled pore structure and low metal impurity content ensure stable electrochemical performance in both lithium-ion and lead-acid battery applications.
Silica improves battery separator performance in several critical ways: (1) Creates controlled microporous structure (pore diameter 0.1-1.0 µm) for optimal ion conductivity; (2) Provides excellent electrolyte wettability through abundant surface silanol groups; (3) Enhances thermal stability — silica does not melt or shrink at battery operating temperatures, preventing separator collapse during thermal events; (4) Increases mechanical strength and puncture resistance against lithium dendrite penetration; (5) Improves cycle life by maintaining pore structure integrity over thousands of charge-discharge cycles.
Yes. Censil battery separator grade silica serves two major battery markets. For lead-acid batteries, it is used as the pore-forming filler in PE (polyethylene) separators — the silica is co-extruded with UHMW-PE and process oil, then the oil is extracted to create the microporous separator structure. For lithium-ion batteries, Censil high-purity silica is used in ceramic coating slurries (with PVDF, PAA, or CMC binders) applied to PE/PP separator films, providing thermal stability and improved electrolyte wetting for EV batteries and energy storage systems.
Censil battery separator grade silica offers several advantages as a China battery separator silica manufacturer: (1) Optimized pore characteristics — controlled particle size distribution ensures uniform micropore structure in separators; (2) Low iron content (Fe ≤500 mg/kg) prevents self-discharge and grid corrosion in lead-acid batteries; (3) BET 100-150 m²/g range specifically selected for battery applications — balances electrolyte absorption with processing efficiency; (4) Cost-effective alternative to imported battery grade silica brands, with shorter lead times and customizable specifications.
Qualifying a new battery separator silica supplier requires: (1) Chemical purity analysis — ICP-MS or ICP-OES for Fe, Cu, Pb, Cd, Ni content; (2) Particle size distribution by laser diffraction — D10, D50, D90, and span; (3) BET surface area by nitrogen adsorption; (4) Acid resistance test — slurry in 1.28 SG H₂SO₄ at 60°C for 24 hours; (5) Separator trial — extrude a test batch, measure electrical resistance, oxidation resistance, and puncture strength per DIN 40742. Censil provides free 200g samples for qualification testing.