Li Metal Battery Breakthrough May Boost Electric Vehicle Adoption

Electric vehicles have been media darlings that dominate the headlines and guarantee huge viewership. But how popular are they really to the consumers? Can the sales really stack up to the media hype?

Actually the electric vehicle adoption is increasing, though a bit on the slow side. According to Auto Alliance, EV makes up only 2.4% of car sales in the U.S. in August 2018. Another automotive study done by Tongji University in China found that only 18.1% of drivers in China are willing to buy an electric car.

Why are the consumers so reluctant to replace their conventional vehicles with their electric counterparts? Despite the great publicity bestowed upon the EV, the sheer cost of buying a new EV is staggering, between US$39,000 and US$49,000 (£31,500~£39,500), according to a BBC report. Even if the motorists are willing to shoulder the big sum of upfront cost or settle for a used EV, the battery life is another huge obstacle that many EV and battery manufacturers have yet to solve. According to a report done by the UK’s Transport Research Laboratory, range anxiety is one of the major obstacles for EV purchases. Non-EV buyers are worried about the range which the current EV battery could achieve, while the EV buyers validate their battery-related concern. However, this is about to change.

Imagine a Lighter and More Powerful Battery
New technology for lithium metal batteries has been invented by a research team comprised of scientists from Stanford University and SLAC. Given the massive size of the EV batteries, it should not come as a surprise that they wasted 25% of their own precious electricity on hauling themselves around. Therefore this lightweight and long-lasting battery, according to the scientists, could be the next-generation battery that the EV manufacturers and consumers are looking for.

The lithium metal battery is way more powerful than lithium-ion batteries by nature, holding at least 33% more power per pound than Li-ion batteries. Plus, the lightweight lithium is used for the positively charged end. Therefore the newly improved battery would be lighter than the conventional EV battery, which uses the heavier graphite. However, the Li-metal battery’s tendency to burst into flames has prevented it from commercialization. Its short life expectancy does not help its case, either.

The research team has made pioneering efforts in solving the Li-metal battery problem. They have published a study on Aug. 26 in Joule. The reason why Li-metal batteries short-circuited or even explodes lies in the dendrites, a band of spike-like lithium matters. As the electrodes are crumbling, the dendrites grow longer. When the dendrites eventually pierce through the separator and reach the cathode as seen on the picture below, they cause a short circuit and in some cases, spontaneous combustion.

Image from Engadget

Stanford scientists have set out to solve the instant inflammation problem, because Zhenan Bao, a professor of materials science and engineering and of chemistry, who is senior author of the Joule study, and Yi Cui, a professor of materials science and engineering and of photon science at SLAC believe that “We’re addressing the holy grail of lithium metal batteries.” Bao also further explained that the Li-metal batteries could be deployed in the next generation of the electric cars, provided that the dendrites issue could be resolved.

The Stanford and SLAC team produced a working battery with their new coating and other commercially available components. The new coating prevents undesirable chemical reactions resulted from the pierced separator between the anode and cathode as well as the growth of the dendrites.

The new battery also managed to provide 85% of the power which it did in the first cycle, whereas the traditional ones can provide only 30% of its first cycle after the same amount of cycles. Their invention “makes lithium metal batteries stable and promising for further development” declared Zhiao Yu, the other co-lead author, a Stanford Ph.D. student.

Battery Efficiency Still Less Than Ideal
However, the research team also noted that there is still work to be done. The efficiency of the new lithium metal battery is still much lower than the current Li-ion batteries.

The scientists are improving the coating in the hopes of giving the capacity retention a boost that is much needed for commercialization. They believe that their invention would be more likely to be deployed in consumer electronics first. After the doubt surrounding the li-metal batteries has been squashed, then their ultimate goal of EV application could be realized.

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