As of 2025, the application of high-precision membrane filtration technology in the lithium-ion battery sector has evolved from early “auxiliary purification” to “core process integration,” and has achieved several key breakthroughs in areas such as materials, structure, system integration, and intelligentization. Below are the five most representative recent advancements:

As of 2025, the application of high-precision membrane filtration technology in the lithium-ion battery sector has evolved from early “auxiliary purification” to “core process integration,” achieving several key breakthroughs in areas such as materials, structure, system integration, and intelligentization. Below are the five most representative recent advancements:

1. Industrial-scale production of organic-solvent-resistant composite nanofiltration membranes achieved.

Breakthrough: Traditional polymer membranes (such as polysulfone and PES) tend to swell and degrade in highly polar organic solvents like DMC, EC, and NMP, which limits their application in electrolyte purification.

Latest update:

Domestic companies—such as Wharton Technology, Lanxiao Technology, and Sino Water—have successfully developed crosslinked polyimide (PI)- or polybenzimidazole (PBI)-based composite nanofiltration membranes that can operate stably for over 6,000 hours in environments with temperatures exceeding 80°C and high concentrations of organic solvents.

The molecular weight cut-off (MWCO) is precisely controlled within the range of 200–500 Da, enabling efficient removal of LiPF₆ decomposition products (such as HF and POF₃) as well as metal ions (Fe and Ni < 1 ppb).

Continuous replacement of the distillation process has been implemented in the electrolyte production lines of leading companies such as CATL and Tianci Materials, reducing energy consumption by more than 35%.

2. Ceramic ultrafiltration membranes used for NMP slurry recovery extend the membrane lifespan to over 3 years.

Background: Traditional polymer membranes tend to become contaminated and clogged when used with high-viscosity slurry waste containing PVDF/NMP, leading to frequent replacements.

Breakthrough:

The next-generation multi-channel silicon carbide (SiC) ceramic ultrafiltration membrane (pore size: 20–50 nm) features:

High temperature resistance (>150°C), resistant to strong alkalis/organic solvents;

Surface superhydrophilic modification boosts anti-fouling performance by a factor of three;

Online backwashing + chemical cleaning (CIP) available, with a flux recovery rate exceeding 95%.

In the recycling systems developed by Guoxuan High-Tech and Svolt Energy, a single membrane module has achieved an operational lifespan exceeding 40 months, with NMP recovery purity reaching 99.9%, meeting the standards for reuse.

3. Gradient-pore-structure membranes enable “one-step” multi-stage separation.

Innovative Design: Asymmetric gradient pore membranes (with a dense surface layer and a porous support layer inside) are prepared via electrospinning or phase inversion techniques.

Application effect:

In the treatment of electrolytes from retired batteries, a single membrane can simultaneously retain micrometer-sized particles, colloids, and large-molecular organic substances while allowing small-molecule solvents and lithium salts to pass through.

By reducing the traditional multi-stage process of “pre-filtration + fine filtration + adsorption,” the system’s footprint is reduced by 50%, and investment costs are lowered by 25%.

The gradient PVDF-HFP membrane developed in collaboration between the Institute of Process Engineering, Chinese Academy of Sciences, and Enjie Co., Ltd. has been validated in a pilot project.

4. Smart membrane systems integrated with AI-powered predictive maintenance

Technology Integration: Embedding IoT sensors, digital twins, and AI algorithms into membrane filtration units;

Feature Highlights:

Real-time monitoring of parameters such as transmembrane pressure difference (TMP), flux decline rate, and turbidity;

Predict the trend of membrane fouling based on machine learning models, and automatically optimize backwash cycles or switch to backup modules.

BYD’s “Lighthouse Factory” has deployed this system, resulting in a 20% extension of membrane service life and a 60% reduction in unplanned downtime.

5. Derivative technology of perfluorosulfonic acid (PFSA) proton exchange membranes for lithium-ion battery purification

Cross-sector innovation: Drawing on fuel cell proton exchange membrane technology to develop nanofiltration membranes with charge-selective properties.

Advantage:

Utilizing the Donnan effect, it selectively repels cations (such as Fe²⁺ and Cu²⁺) while allowing Li⁺ to pass freely.

In the purification of lithium hexafluorophosphate (LiPF₆) solutions, the removal rate of metallic impurities exceeds 99.99%, while lithium loss is less than 0.5%.

Enterprises such as Dongyue Group and Kerun New Materials are advancing pilot-scale verification.

Conclusion

High-precision membrane filtration technology is shifting from “passive filtration” to “active regulation,” emerging as a key technological pillar for green, intelligent, and high-value lithium-ion battery manufacturing. As domestically produced membrane materials match international standards in performance and system integration capabilities continue to improve, China is poised to assume a leading position in the global supply chain for high-end lithium-ion battery consumables.