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View Diary: Breakthrough: New Flow-Battery Design Provides 10-Fold Improvement (143 comments)

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  •  It is probably a bit early to pronounce this (29+ / 0-)

    as a breakthrough that will suddenly solve all battery problems.  In these situations you have to wait for the technology to be developed to see just how useful it will be.  For instance, the article says the new technology has a 10 fold energy density improvement over previous flow batteries, but those batteries had lousy energy density.  It does not say what the energy density is compared to current lithium batteries.

    The refueling aspect is very promising, as range anxiety is the biggest problem with pure electric cars.

    If it makes large scale storage of electric power more efficient, that might be the biggest contribution.

    This sort of  technology article is great.  But it is hard to tell which advances will make a big difference.  So we have to research as many different options as possible.

    "The trouble with the world is that the stupid are cocksure and the intelligent are full of doubt." Bertrand Russell

    by Thutmose V on Wed Jun 22, 2011 at 08:55:09 PM PDT

    •  Energy density (5+ / 0-)

      They are claiming a factor of two reduction in size of an equivalent system. That doesn't seem to be a lot given that it's the initial claim.

      I wonder if the fluids have pollutants and would be an environmental problem unless carefully recycled.

      •  The ingredients are essentially identical (13+ / 0-)

        with those in a state-of-art lithium battery. Lithium metal oxide spinels (cobaltites, manganates etc), alkyl carbonates and carbon or similar counter electrodes.

        No, you wouldn't want to spill these into the sewer - aside from any pollution concerns (which are real enough) the ingredients are pricey. You'd want to keep them contained to save waste.

        On the volumetrics and energy densities of the devices - I think too much is being made of those claims, though both claims are positive versus current technology. You cannot, for instance, make lithium cobaltite less dense and have lower volume occupied.

        What is more critical, in my view, is the simplified cell designs resulting in lower costs of construction - and, possibly, safer process lines for cell fabrication.

        •  Fractal percolation (8+ / 0-)

          I like the description of the "percolating conductor networks" formed by the carbon nanoparticles (Ketjen black) in the "Cambridge crude":

          Interactions between nanoscale particles are typically dominated by colloidal rather than gravitational forces. In solutions of high salt concentration such as ionically conductive electrolytes, surface charges are screened and attractive London–van der Waals attractions dominate, resulting in ‘hit and stick’ behavior that forms fractal particle networks by DLCA [diffusion-limited cluster aggregation].

          Cambridge crude beats Texas tea.

          •  Rec'd (1+ / 0-)
            Recommended by:
            ItsSimpleSimon

            As I did for the diary, I am rec'ing this because it gives hope for all of humanity. I understood less than half of it, but enough to know that it was a positive step in the right direction. And it represents a technological advancement that future research can build upon.

            I don't need to know exactly how gravity works to know that it is important.

            So to all you engineers and physicists out there...thank you!

            There are three kinds of people. Those that are good at math and those that aren't.

            by beefydaddy18 on Thu Jun 23, 2011 at 08:51:52 AM PDT

            [ Parent ]

          •  I am an electrical engineer (1+ / 0-)
            Recommended by:
            Quicklund

            (of the semiconductor variety), and frankly I couldn't understand a damn thing from this quote:

            Interactions between nanoscale particles are typically dominated by colloidal rather than gravitational forces. In solutions of high salt concentration such as ionically conductive electrolytes, surface charges are screened and attractive London–van der Waals attractions dominate, resulting in ‘hit and stick’ behavior that forms fractal particle networks by DLCA [diffusion-limited cluster aggregation].

            But nonetheless I am glad somebody understands this sh*t and I'm sure glad somebody is pushing the envelope in battery development!
            •  Also an EE (of the held many non-EE jobs variety) (4+ / 0-)

              I will take a stab at it..

              At this scale the tiny particles stay in suspension because viscosity is stronger than gravity.  With the addition of salt to the solution charged ions result and these tend to stick to the surface of the tiny particles held in suspension. As the particles meander through the gel (as per that gels tolerance for meandering) the particles bump into one another, the ions trapped on them cause the tiny particles to stick together and form little clusters.

              I wonder how wrong I am on a scale of 0 to 99, and then again from 237 to 521.

              Stop. Stand up. Make a sign. Walk around in public. Be polite and orderly and the rest takes care of itself. Want to shake up the Plutocrats? Demonstrate your attention to politics.

              by Quicklund on Thu Jun 23, 2011 at 02:58:22 PM PDT

              [ Parent ]

              •  Basically you are on the right track (1+ / 0-)
                Recommended by:
                Quicklund
                Interactions between nanoscale particles are typically dominated by colloidal rather than gravitational forces

                Nanometric particles (colloids) will interact based on their surface charge. You can measure this charge using a specialized device (it measures what is termed the zeta potential). Ideally, in a well dispersed colloid where the measured zeta potential is high, the particles will mutually repel one another - due to their like charge.

                Settling due to gravitational forces dominates when particles are not nanometric - for instance at a larger than micron scale. The larger they are, the faster they fall, even if each particle bears a relatively high charge.

                In solutions of high salt concentration such as ionically conductive electrolytes, surface charges are screened and attractive London–van der Waals attractions dominate, resulting in ‘hit and stick’ behavior that forms fractal particle networks by DLCA [diffusion-limited cluster aggregation]

                This is "fancy science speakin'" for the phenomenon previously known as flocculation. Say you have ions of opposite charge to the surface charge of the colloidal or larger particles. These ions aggregate to the first outer sphere on each particle. If the ions are mutiply charged (sulfate, complex chlorides) then they can bridge two particles together. As this growth process continues the aggregates become larger in total dimension.

                DLCA basically means - we can only grow this sucker as fast as another charged particle migrates through the fluid to join the party. Which migration occurs by diffusion (by definition) which has a rate governed by several factors, including the mass of the particle and it's surface charge, the concentration of the slurry, temperature and so on.

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