Boron in Batteries and Capacitors

Borates enhance protection, performance, and durability of batteries

Energy storage systems are experiencing tremendous growth—largely due to rising electricity prices, falling production costs, and investment incentives. Among them, batteries and capacitors are devices that are enabling a transition to cleaner, renewable energy.

To fully reach their potential, batteries and capacitors need high-quality materials, such as boron, that enhance performance and support longer product lifespans. Boron compounds impart benefits across multiple battery and capacitor functions—from electrolyte solutions to surface treatments. By using boron, you can lower costs, save energy, and improve durability.

Of course, battery and capacitor production environments are complex; purity is essential. Contaminants in additives can derail sensitive processes and render your product worthless. That’s why you need a partner who not only meets rigorous quality standards in every batch but also has the technical acumen to ensure the right borate concentration for your needs.

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The role of borates in lithium-ion batteries

Borates serve two main purposes in lithium-ion battery manufacturing: Protection and lowering energy use. 


The higher your battery’s charge rate, the more likely adverse lithium dendrite deposits will form on the graphite-based anode. These cause battery cells to short out, fail, and even ignite fires in exceptional circumstances. Applying a borate surface coating protects against lithium deposition. Research has also shown borates improve the stability of the solid electrolyte interphase (SEI).

Used in lithium-ion battery electrolytes, these borate compounds improve thermal and cycle stability:

  • Lithium bis(oxalate) borate (LiBOB)

  • Lithium tetrafluoroborate (LiBF4)

  • Lithium difluoro (oxalate) borate (LiDFOB) 

Conserving energy

The graphitization process is critical to your lithium-ion battery’s performance, affecting attributes such as energy density, cycle life, and rate capability. Incorporating boron before graphitization saves energy by lowering the necessary treatment temperature. In lithium-ion batteries, borates:  

  • Improve electrochemical properties

  • Increase crystalline structure, making lithium ion transfer easier

  • Enable a higher capacity than pure graphite (437 mAh/g vs 372 mAh/g)

Learn more about battery-grade lithium from Rio Tinto

Borates in capacitors

Boron positively impacts a capacitor’s ability to store energy. Whether you’re producing a dry or wet capacitor, refined borates act as cleaning agents for the dielectric medium and are commonly incorporated into the electrolyte solution.

Wet capacitors

Forming an effective dielectric oxide film between your metallic conducting plates is critical. First, the metallic plates must be cleaned, a task suitable for boric acid, borax decahydrate, or ammonium pentaborate. Then, submerging plates in an aqueous electrolyte solution—containing highly pure boric acid and either ammonium or sodium borate—forms the dielectric oxide film.

Dry capacitors

Unlike wet capacitors, dry capacitor electrolytes are non-aqueous, have low-conductivity, and range from viscous liquids to nearly solid masses. Typical borate-based mixtures include:

  • Glycol-ammonium borates
  • Ammonium acetates borates
  • Amine borates

Chlorides, nitrates, sulfate, and iron are impurities that negatively impact electrolyte performance. We subject our refined borates to rigorous quality control, minimizing the risk of contaminants.

Learn more about our special battery-quality grade options for borax decahydrate, Optibor®, and ammonium pentaborate.

Why choose U.S. Borax for batteries and capacitors?

Rigid quality and purity standards

Your product’s performance depends on consistent inputs, free of contaminants. Our high-quality standards ensure you get refined borates that are:

  • Free of impurities
  • Less prone to caking
  • Chemically and physically stable
Leading research and development

We’re more than a trusted supplier. Our team has a proven track record for innovation, including both product development and process improvement. We conduct collaborative research with leading organizations to advance understanding of how borates can enhance battery and capacitor performance.

See an example of our peer-reviewed research

Trusted technical support, responsive customer service

From detailed safety data sheets to meticulous product traceability to process and product consulting, our team is here to deliver what you need.

20 Mule Team Borax Products

Recommended for batteries and capacitors

Optibor logo

Available in special quality grade, ammonium pentaborate forms an effective oxide film when used in electrolytes for both wet and dry capacitors.

Learn More  

Optibor logo

Capacitor producers rely on the purity of special grade borax decahydrate for use in electrolytic capacitors.

Learn More  

Optibor logo

Available in multiple grades to accommodate your process, our Optibor products deliver a highly pure and consistent boric acid supply.

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More about borates in batteries and capacitors

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U.S. Borax, part of Rio Tinto, is a global leader in the supply and science of borates—naturally-occurring minerals containing boron and other elements. We are 1,000 people serving 650 customers with more than 1,800 delivery locations globally. We supply around 30% of the world’s need for refined borates from our world-class mine in Boron, California, about 100 miles northeast of Los Angeles.  Learn more about Rio Tinto.

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