Making Better Batteries With Metal Oxide & Graphene Composites

Scientists from Pacific Northwest National Laboratory and Princeton University have created better materials for batteries - materials that assemble on their own into durable nanocomposites.

Transcript

00:00:04 [Music] one of the big challenges that we face is to reduce our dependence on imported oil and we would like to Electrify our transportation sector our vehicles one of the goals of the Department of energy is to do that through turning our transportation Fleet running it on batteries if we could or electric vehicles one of the challenges there is

00:00:31 that our batteries really don't perform well enough cannot run a car long enough or fast enough for what we truly need for the customers to be happy in order to achieve this goal we need to develop high capacity batteries including n iron batteries the current anode material used in N iron battery is carbon based material so ideally we would like to at least double the capacity of the

00:01:01 materials T oxide is a high capacity unkn material however the stability of the material is very poor as you charge discharge the battery the capacity Fades very fast and capacity comes down very quickly that is the problem with these real high capacity anod materials like tin or silicon which is kind of the Holy Grail is we know they have tremendous capacity they have terrible cycle life

00:01:29 and that unre repea charge and discharge they will always tear themselves apart essentially tear the structure apart so in this particular paper we're trying to resolve that problem by combining T oxide with other high conductive materials so in this case the graphite is separated into single mon seats our collaboration with Pacific Northwest National Laboratory started out with our

00:01:57 invention on the production of uh functionalized graphine so I'd like to explain what this functionalized graphine is unlike the uh graphine that's peeled off from graphite by using Scotch tape what we do is something that dates back to 1859 where a British chemist bro oxidized graphi in strong acids we split this graphite oxide to more than

00:02:29 80% single sheet functionalize graphine oxide we do that by thermally exfoliating it then we mix graphine and T oxide in a very special way so that the surface chemistry of the graphine is modified by surfactant to match the chemistry of te oxide surfactants are commonly used materials we think of more as detergents or soaps so in the case of detergents that we use in laundry soaps

00:02:59 or hand soaps dirt for the most part or Organics or Oils are not missable in water just like oil and water in a salad dressing they do not mix so a surfactant molecule actually has on one end part of the molecule would like to be in water the other end it is hydrophobic or does not like water and so what it has the ability to do is surround for example an oil particle and bury the tail as we

00:03:22 call it or the hydrophobic portion in the oil where it wants to be but then it leaves the outer portion of the molecule that likes water so that then you can come in and put in a waterbased solution that then you can precipitate the ten oxide or the silica or the phases that are the active materials for the battery when you mix this molecular precursors you stir them in a solution to self

00:03:45 assemble into highly ordered materials in which the T oxide is sandwiched between graphing seeds so we perform very careful transmission electron microscopic study of this material to reveal what kind of micro structures we have and no magnification you can clearly see the N structure with dark and white bands so the dark bands are the T oxide and the

00:04:15 white bands are the graphing materials if you go to high resolution transmission electron microscopy you can begin to see the atomic ples of the T oxide and atomic ples of the graphing material so in this particular case we can clearly see how the cryst in t oxide nanop particles are sandwiched between four or so NS of graphing seats now this new material has very special properties

00:04:51 the graphing seats function as a good conducting material to connect the electrons in the battery at the same time time when you charge discharge the electr material the te oxide will expand and the shrink however because the sandwich between the graphing seats the whole material doesn't fall apart therefore you retain the good stability of the electral material and the reason

00:05:21 this work is important is that it's a possible route to improving the battery performance so that it might be able to meet the goals of the Department of energy has established for vehicles and it is an approach that though thought about in a number of ways has been very difficult to do in an easy synthesis route that can produce a lot of material at a low cost potentially and I think

00:05:44 that's why many people look at this as perhaps this kind of an approach may be able to solve some of these big hurdles that we've faced for many [Music] years