First-Designed Product: Superior Battery Electrolytes

This project has been proposed to CalSEED, a program of the California Energy Commission funded by California electric ratepayers to develop innovative energy technologies that can save ratepayers money in ways that would not otherwise get developed.

NSI's nanostructural self-assembly system will be exploited to produce solid-phase battery electrolytes for conducting cations (positively charged protons and metal ions) between the electrodes within all kinds of batteries.  Cation conduction [see Note 1 for technical explanation] is a necessary and essential part of all batteries.  We are most interested in lithium-ion and lithium metal batteries due to the low mass of lithium ions and the commercial prevalence of such batteries in the battery market.

The functional superiority of the electrolyte will be provided by two different solutions: 

First, sulfonate groups in immediate proximity to each other, thus shortening the "ion hopping" distance to near to theoretical limits (less than 100 picometers), and lowering energy losses from ion-hopping inefficiencies [see Note #2 for explanation].  This has the potential to be a revolutionary improvement in battery functionality.  (Please also request the PowerPoint presentation about NSI electrolytes.)

Sulfonate groups are negatively charged, which is why they are well suited to "conduct" positive ions [see Note #3].

Second, sulfonate groups separated by exact distances to allow sulfonate rotation and "bucket brigade" handoff of cations from one sulfonate group to its nearest neighbor.  Since the ideal separations for hand off might depend on the size of the cation, we'll need to make and test many candidate separations. 

The end result?  Ions will lose less energy, create less waste heat, and move more quicklyin greater numbers.  This is anticipated to 

    1) increase energy density (energy per weight and volume of battery),
    2) increase power density (faster charging, faster discharging),
    3) enhance energy efficiency (more power out compared to power in),
    4) extend battery lifespan (number of charge-discharge cycles), and
    5) improve battery safety.

Revenue will derive from licensing fees, royalties, R&D contracts and consulting services.

Note #1:  The internal cation current (within the battery) is equivalent to the external electrical current produced by the battery. In other words, there is a one-to-one relationship between negatively charged electrons delivered to perform work and the positive charges on protons or metal ions that migrate from electrode to electrode within the battery. [Return to main text.]

Note #2:  Each ion "hop" within a battery causes loss of energy (i.e., resistance) which decreases energy density (by resistance losses), decreases power density (by heat-limitations on battery performance), shortens battery lifespan (hot batteries age more quickly), and compromises battery safety (hot batteries are more likely to short-out, burn or explode). Charge repulsion between sulfonate (or phosphonate) groups in polymer electrolytes normally causes sulfonyl groups in existing-art polysulfonate polymers to distribute themselves evenly throughout the polymer volume. This mandates ion hopping. To overcome this, intercalating agents (e.g., iron phosphate nanocrystals) are mixed into lithium-ion battery electrolytes to provide "islands" to shorten the hopping distances. But these intercalating agents are also randomly distributed, and so this is only an incremental improvement. NSC's vector-directional polymer design places sulfonates immediately adjacent to each other (0.35 nm center-to-center separations, < 0.1 nm surface-to-surface separations), which is predicted to reduce hopping to its theoretical minimum. [Return to main text.]

Note #3:  Sulfonate groups are also chemically stable and strongly acidic. The high acidity (analogous to sulfonic acids) means that sulfonate groups have minimal bonding or "stickiness" to protons, and low bonding or stickiness to lithium, transition metal ions (vanadium, manganese, cobalt, nickel, zinc), heavy metals (mercury, lead), and rare earth metals (e.g., cerium). Sulfonate and phosphonate groups are the perfect first-choice for ion conductivity, being the anions of choice for the state-of-the-art commercial electrolyte polymers (e.g., Nafion). [Return to main text.]