"No battery yet exists that will provide long-lasting power and still fit inside devices this small," said Bruce Dunn, a materials science professor from the UCLA Henry Samueli School of Engineering and Applied Science. "Our team of engineers and chemists are establishing the enabling science for a new battery that represents a real paradigm shift," he told NewsFactor.

Dynamic Dimensions

The shift from old to new involves a simple change of geometry. Traditional batteries have a two-dimensional array of positive and negative electrodes stacked on top of one another like sheets of paper. Increasing battery power means adding more electrode layers, more weight and more size. Dunn and his team propose a three-dimensional array of electrode rods stacked next to each other like pipes on a flatbed truck.

"By making this change in geometry, one can get more anodes and cathodes per unit volume and hence more 'bang per buck,' which you need if you are dealing with batteries at the micrometer -- or nanometer -- scale," chemistry professor and UCLA Exotic Materials Institute director Fred Wudl told NewsFactor.

Packed and Compact

With each electrode rod only a thousandth of a centimeter wide, the 3-D design also reduces the distance ions have to travel, keeping the battery compact and tightly packed.

"By building small batteries with 3-dimensional architectures, you can limit diffusion lengths," said Sarah Tolbert. A UCLA assistant chemistry professor, Tolbert is perfecting self-assembly, or spontaneous formation, processes to produce cathode materials for MEMS batteries.

"Just like the flow of water, charge and ion flow, or diffusion, usually decreases with size," she told NewsFactor. "In a 3-dimensional architecture, you can put active elements near each other so that chemistry of the battery can occur quickly, and electrons can get out of the battery rapidly to do useful work."

"A more efficient path for the movement of ions also means less power loss and a longer-lasting battery," Dunn added.

Well Dunn Nano Rolls

The group is currently designing a battery roughly five millimeters in size, which presents significant design challenges. "We're going to use fairly well-known lithium battery materials," Dunn said. "The hard part is fabricating it into a structure. That's where the real engineering emphasis will be."

To fabricate the batteries, the team places electrode materials -- nano-sized rolls of graphite and/or carbon doped with lithium -- into tiny molds made from silicon chips. After the electrodes harden, fabricators etch away the silicon mold, leaving behind the three-dimensional electrode structure.

Techno-Think: It Must Shrink

As cell phones, video cameras, computers, and scores of other electronic products continue to shrink, so must their batteries, which today contribute up to 35 percent of a laptop computer's weight. Despite the urge to surge the power while shrinking the device, five years may still pass before lightweight 3-D batteries arrive on the market, Dunn said. Market dynamics, however, make these batteries a must.

"The portable power market is so vast that if we are very successful, I am sure our concepts and designs will be used to try to make 3-D power supplies," Dunn explained. "It's exciting. We have the opportunity to take electrochemical materials and designs in a new direction."