New materials can help make batteries flexible and energy-dense enough to power displays like this one on bendable, implantable, and wearable electronics.
The high-performance materials used in the traditional rechargeable lithium-ion batteries aren't flexible, and most materials that are bendable can't store enough energy to run a display. Flexible battery substrate materials, such as plastic, paper, or textiles, can't withstand the high temperatures required to build electrodes using the high-quality inorganic materials of rigid batteries.
A flexible inorganic, thin-film lithium-ion battery made of all solid-state materials delivers enough energy density to power this bendable display. (Source: Nano Letters)
Keon Jae Lee, a professor of material science, and his colleagues at the Korea Advanced Institute of Science, joined by researchers at Seoul National University, have devised a bendable, inorganic, thin-film lithium-ion battery made of solid-state materials (registration required). Its peel-off temporary substrate material, made of mica, can tolerate the high temperatures (around 700C) used to anneal lithium cobalt oxide electrodes, which are commonly used in lithium-ion batteries for portable electronics.
The team wanted to take high-performance lithium-ion battery materials and make them flexible. To do so, they used the universal transfer approach. After building the battery on the temporary mica substrate, they used an annealing process that created a high-quality lithium cobalt oxide cathode. The battery was completed with a solid electrolyte and a lithium-metal anode. The annealing process also helped the researchers delaminate the battery from the mica using tape by weakening the intermolecular forces between layers.
The battery's flexible substrate was then made by encapsulating it in flexible sheets of polydimethylsiloxane. The final battery is 10 microns high.
The researchers say their battery has an energy density of 2,200µWh per cubic centimeter -- higher than any previously reported flexible battery. The team supported this performance with finite element analysis simulation. Lee and his colleagues also integrated the battery with a flexible organic LED display -- they say this is the first time this has been achieved.
The team says this new transfer approach can be applied to other flexible applications, such as thin-film nanogenerators, thin-film transistors, and thermoelectric devices. The researchers are investigating a one-step laser liftoff process for delamination that will enable high-volume fabrication of large-area lithium-ion batteries. They are also devising ways to increase the batteries' energy density, such as eliminating some of the external polydimethylsiloxane sheets.
Jim, thanks for acknowledging what a big deal flexible batteries are. You're right, I guess we tend to get distracted by the flexible displays. But the real innovation is in the batteries, and you've clearly described what they bring to portable electronics design.
Jim, it was only a half tongue-in-cheek comment. I was surprised to learn how roughly electronics are treated by some young people, especially DVDs. Gee, thanks for all those scratches on my rental movie! Since ruggedization of removable media and systems is costly, it's usually only the military and industrial versions of electronics that get that protection.
Charles, having the ability to create a new product architecture knowing the battery is no longer a rectangular block will allow product designers much flexibility. I've been developing hand-held and portable electronic products for a long time and the very first considerations to a products' overall size, weight and form-factor are (1) the battery and (2) the display. Defining those two elements is an 'up-front' task that must be thoroughly specified before you can begin product layout.
Regarding your question if flexible displays always require a flexible power source, well, no; not at all. But when concept products show-casing flexible display technologies first started showing up at CES about 10 years ago, the product architects were constrained to designing with rectangular prismatic Lithium-Ion cell packs; and those large cumbersome bricks put a real damper on the big "Gee-Whiz" effect of the flexible displays (think arm-bands, or wrist-worn items for example).
As mentioned, there are several technologies which allow for flexible displays, but never before have designers had the capability for the entire product architecture to fully exploit this new characteristic. So, if displays can bend, and the motherboards are fabricated on flex circuits, it now gives hope that a power source could match the curve of the entire product and become thin, form-fitting and very compelling to new market applications.
JimT: What are a few of the applications for the flexible power source? Does a flexible power source always get used in a flexible display? Or can the application itself be non-flexible but still need the flexible power source?
Reading thru most of the blogger comments so far, I think many of us are commenting on the flexible display as opposed to the real breakthrough of the flexible power source. I was developing advance concepts for flexible displays over 10 years ago – (both electrophoretic bi-stable displays {e-ink}, and Mylar-based Liquid crystal). But a HUGE roadblock was the lack of a flexible power source. This article is reporting on something very big. When you compare the advancement curves of various technologies over the past several decades, (RF Protocols, Miniaturization, Displays, Rapid Prototyping, Batteries, etc.) the battery advancement is -- by far -- the least impressive. This development will certainly put a spike in that curve.
Ann- I know you make the reference to Toddler-Tested Electronics at DARPA as "tongue-in-cheek", but I don't think you're very far off--- After a recent focus group which interviewed military personnel on the likes/dislikes of a new prototype, it was documented that many of the intended military "users" would be young enlisted men ages 18 & 19, who, or course are fresh from the Gaming-Generation, and tend to be pretty rough on electronics.
Nadine, that's a perfect app for flexible electronics in general, including displays. Kids manhandle everything anyway, so why not make electronics more damage-proof? A new definition of ruggedized: is it toddler-proof? Wonder if DARPA is testing stuff on toddlers yet.
Yes, Chuck, just a few apps since then :) For flexible displays, the apps I see mentioned most often are watches and other wearable computers, medical devices, and signage. I think Nancy's right: once the tech is available, they will be all over the place and we'll wonder how we ever did without them.
I can remember reading about two potential plastic battery technologies more than a decade ago. I'm not talking about using plastic as an armature. There were two developments; one was more like a cap for charge storage; the other was like an organic plastic. I can also remember about film batteries which was more like plastic armature with the media deposited on the plastic film.
New versions of BASF's Ecovio line are both compostable and designed for either injection molding or thermoforming. These combinations are becoming more common for the single-use bioplastics used in food service and food packaging applications, but are still not widely available.
The 100-percent solar-powered Solar Impulse plane flies on a piloted, cross-country flight this summer over the US as a prelude to the longer, round-the-world flight by its successor aircraft planned for 2015.
GE Aviation expects to chop off about 25 percent of the total 3D printing time of metallic production components for its LEAP Turbofan engine, using in-process inspection. That's pretty amazing, considering how slow additive manufacturing (AM) build times usually are.
A $1,500, hand-operated, bench-model, plastic injection machine crowdsource-funded via Kickstarter can be used to mold small, quality, plastic parts inexpensively, on demand.
The federal government is launching competitions to kickstart three more manufacturing innovation institutes, including one focused on Lightweight and Modern Metals Manufacturing Innovation.
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