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Views: 2361 Author: Site Editor Publish Time: 2026-11-09 Origin: Site
Surfactants can modify the crystal morphology of metal oxides, inhibit hydrogen evolution, suppress dendrite growth, reduce corrosion, and delay electrode passivation. Emulsions prepared with surfactants can function as "micro-reactors" and prevent the agglomeration of nanoparticles.
This paper reviews research progress regarding the use of surfactants in battery material preparation and spent battery recycling. With depleting global energy resources and environmental degradation, the development of eco-friendly new energy has garnered widespread attention, where new energy materials play an essential guiding and supporting role. Battery materials primarily encompass cathodes, anodes, electrolytes, and separators, which are critical components for electrical energy storage and supply.
Currently, battery materials are trending toward nanoscale dimensions. Nanomaterials feature unique microscopic morphologies, high lithium intercalation capacity, high energy density, and long cycle life. However, critical challenges—such as controlling nanoparticle agglomeration and size, improving the limited contact area between electrode materials and electrolytes, and enhancing electrolyte corrosion inhibition—all require the use of surfactants.
Surfactant molecules consist of hydrophobic and hydrophilic groups. In solution, they can self-assemble into ordered aggregates such as micelles, reverse micelles, and vesicles, which serve as "micro-reactors" for preparing nanoparticles. Surfactants can also induce directional alignment on carriers, preventing nanoparticle agglomeration, controlling particle size, and improving electrode electrochemical performance. Surfactants have demonstrated vital utility in fabricating battery catalysts, synthesizing electrode materials, acting as corrosion inhibitors, and recycling spent batteries.
Surfactants play an important role in the fabrication of catalysts for ion-exchange membrane fuel cells, primarily via microemulsion methods. Microemulsion systems are divided into normal micellar and reverse micellar systems:
Normal micellar microemulsion systems: Their main drawbacks are the difficulty of separating and purifying particles from the microemulsion and the high consumption of reagents during processing.
Reverse micellar method: When used to prepare electrocatalysts for proton exchange membrane fuel cells (PEMFC), particles synthesized via this method are less prone to agglomeration, exhibit controllable size, and offer good dispersibility compared with other chemical routes. With simple equipment and processing requirements, it is a promising method for nanoparticle preparation.
The main functions of surfactants in preparing nanoparticles via the reverse micelle method include:
Forming reverse micelle systems to control particle dimensions;
Reducing particle agglomeration;
Controlling particle shape, crystal morphology, and related properties.
Surfactants currently used in preparing electrode materials primarily include CTAB, sodium 2-ethylhexyl sulfosuccinate, nonylphenol ethoxylate (NPE), ethylene oxide (EO) and propylene oxide (PO) triblock copolymer EO100PO70EO100, P123 (EO20PO70EO20EO20PO70EO20), PEO600, Tween-80, Span, Triton X-100, sorbitan monooleate, SDBS, SDS, cyclohexane, fluoroalkyl quaternary ammonium salts, oleic acid, and sodium 4-styrenesulfonate.
Common preparation techniques include phase transfer, precipitation, self-assembly, templating, and sol-gel methods.
Using SDBS, CTAB, Triton X-100, and Brij56 [C16H33(OCH2CH2)8HC16H33(OCH2CH2)8H], MnO2MnO2 with different structures and electrochemical properties can be synthesized:
MnO2MnO2 prepared with SDBS as a template hinders battery cycling performance;
CTAB only slightly enhances cycling performance;
Triton X-100 provides favorable discharge capacity and cycling stability;
Using Brij56 as an electrolyte additive in electrodeposition yields nanoscale MnO2MnO2 cathode materials with excellent cycling performance and high discharge capacity.
P123, sodium 4-styrenesulfonate, CTAB, and an oleic acid/kerosene molten mixture can each be applied to prepare lithium battery cathode materials:
P123 template: LiCoO2LiCoO2 electrodes prepared via the sol-gel method exhibit good cycling performance with simple processing and low cost.
Sodium 4-styrenesulfonate template: Using FeCl3FeCl3 as an oxidant produces a sulfur-polypyrrole (S-PPy) composite material. When used as the cathode in Li/S-PPy batteries, discharge capacity and cycling performance improve significantly.
CTAB template: Hydrothermally prepared LiFePO4LiFePO4 cathode materials show increased discharge capacity, reduced cost, and lower toxicity.
Oleic acid and kerosene molten mixture: LiFePO4LiFePO4 combined with nanoscale TiO2TiO2/graphite composite forms a LiFePO4/TiO2LiFePO4/TiO2 composite electrode. Compared to conventional lithium batteries, it exhibits lower energy density but virtually no capacity loss over 700 cycles, achieves current efficiency up to 100%, and offers durability, low cost, and high safety.
These results indicate that surfactants play a significant role in preparing cathode materials, with the oleic acid and kerosene molten mixture surfactant system yielding particularly strong LiFePO4/TiO2LiFePO4/TiO2 composite electrode performance.
Surfactants not only control particle size and promote ordered crystal arrangement, but also regulate porosity, thereby enhancing the electrical properties of the resulting electrodes:
Ulagappan et al. first synthesized tin-based mesoporous materials (pore diameter of 3.2 nm) using the cationic surfactant sodium 2-ethylhexyl sulfosuccinate as a template.
CuOCuO surfaces modified by the surfactant CTAB exhibit an ordered needle-like crystal structure, increasing the contact area between CuOCuO and the electrolyte. Adjusting the CTAB dosage can control the porosity of tin-phosphate materials and improve battery cycling performance.
Composite surfactants provide synergistic corrosion-inhibition effects. Controlling Cu-Sn particle dimensions via Triton X-100 and n-hexanol ratios yields Cu-Sn nanoparticles that, when assembled into lithium-ion battery anodes, exhibit higher cycling capacity and reversible specific capacity.
Combining non-ionic surfactants containing polyoxyethylene groups with indium hydroxide additives significantly suppresses battery self-discharge while improving the electrochemical performance of rechargeable alkaline zinc-manganese batteries.
Nanoscale tin dioxide/carbon composites and tin-based oxide/carbon composites prepared in P123-ethanol solution exhibit superior cycling performance compared with conventional nanoscale tin-based materials when used as lithium-ion battery anodes.
Self-discharge of the zinc electrode in alkaline zinc-manganese batteries is a major factor limiting battery service life. Traditionally, mercury or mercuric salts were used to suppress self-discharge. However, mercury is highly toxic, hazardous to the environment, and accelerates zinc electrode deformation. Consequently, eliminating or replacing toxic mercury is essential.
Current mercury-free initiatives in alkaline zinc-manganese batteries focus on two approaches: adding corrosion inhibitors to the electrolyte or incorporating them directly into the zinc anode. Evaluated additives include inorganic inhibitors and organic mercury-replacing inhibitors, with organic alternatives primarily consisting of anti-corrosive surfactants:
An evaluation of 6 surfactants with different hydrophilic chains regarding their inhibition performance on zinc in KOH solution showed that potassium decyl (octa)oxyethylene ether phosphate reduced zinc powder hydrogen evolution by 70.6%, achieving an inhibition efficiency of 78.7%.
Because single additives rarely deliver significant overall electrochemical improvements, research focuses on high-efficiency surfactant blends:
Comparing organic additives YLZX (alkyl trimethyl ammonium bromide with C12–C16C12–C16 alkyl chains), YZ (a blend of alkylphenol ethoxylate and alkyl ethoxy sulfate with C10–C17C10–C17 alkyl chains), lauryl alcohol ethoxylate blended with alkyl ethoxy sulfate, PEO400, SDS, and Tween-20 showed that YLZX and YZ notably inhibit hydrogen evolution and dendrite formation without compromising zinc electrode discharge performance.
The SDBS and Tween-20 composite system exhibits excellent corrosion inhibition, delayed passivation, and clear synergy, significantly increasing zinc electrode discharge capacity and achieving an inhibition efficiency of 83.26% under optimal blend ratios.
While most studies focus on adding inhibitors to electrolytes, fewer investigate additions directly into electrode materials. Current studies on adding SDBS and CTAB to zinc powder show that simultaneous addition improves battery charge-discharge efficiency, capacity retention, and cycle life. However, while organic inhibitors added to the anode reduce self-discharge in zinc-nickel batteries, they still do not fully meet commercial requirements.
Surfactants form emulsions that improve the transport rate of specific metals:
An emulsion liquid membrane composed of kerosene, surfactant (Span-80), carrier, and internal aqueous ammonia was used to separate and concentrate cadmium ions from spent nickel-cadmium batteries. In a 100 L reactor scale-up experiment, the cadmium migration rate reached 93.3%, while nickel migration was only 14.6%, achieving effective separation of cadmium and nickel ions.
Surfactants can also lower the activation energy of interfacial reactions between carbon and manganese oxide, significantly impacting reduction rates. After spent batteries are sorted, crushed, and screened, the manganese dioxide is pelletized with carbon reductant, sintered, and reduced in an induction furnace to produce manganese steel. Experimental results indicate this process can be directly applied in cast steel production to process spent batteries.
Surfactants serve vital functions in battery systems: modifying the crystal morphology of metal oxides, inhibiting hydrogen evolution and dendrite growth, providing corrosion inhibition, and forming emulsions that act as "micro-reactors" to prevent agglomeration. Surfactants used include anionic, cationic, non-ionic, and specialty surfactants across proton exchange membrane fuel cells, lithium-ion, alkaline zinc-manganese, zinc-air, and nickel-cadmium batteries. The composite electrode prepared using an oleic acid and kerosene molten mixture surfactant system represents a favorable route. Nano lithium-ion battery anodes prepared from P123-containing ethanol solutions show superior cycling performance, though technical challenges remain.
Although surfactants improve electrode cycling performance and charge-discharge efficiency, gaps remain before full practical implementation; for instance, the charge-discharge efficiency of many electrodes fails to exceed 99.5%. In battery recycling, the utilization of surfactants remains limited. Surfactants can inherently act as collectors, depressants, and frothers, meaning flotation techniques are fully viable for metal separation during battery recycling—an area where surfactants could play a larger role.
Furthermore, existing studies rely heavily on conventional surfactants with relatively high costs, while research into novel surfactants remains insufficient. The electrochemical performance of novel polycarboxylate, naphthalene-based, and biosurfactants with strong dispersion characteristics in battery materials remains largely unexplored.
