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Battery Breakthrough Could Lead to Lighter EVs with Longer Ranges

A new spin on old tech could increase battery range three-fold.

byRob Stumpf|
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Given the recent rise in popularity, many people looking to buy a new car in the next five to 10 years may consider an electric car as their next purchase. Those who are still sticking to traditional gasoline-powered cars are reluctant to switch, though, because of their concerns about battery life, how long it takes to charge a battery and the lack of adequate public charging infrastructure. But a new breakthrough by the University of Texas at Dallas may be a true game changer and sway the way consumers look at EVs.

The traditional lithium-ion battery has been used in consumer electronics for years. Over time, auto manufacturers like Tesla have begun to utilize the technology to power electric cars. This allowed consumers to charge up their vehicle's batteries at home or on the go, but longer trips were limited to a battery's charge. Once the vehicle required more juice, the owner would need to find a charging station, plug in their vehicle for up to an hour and a half, and wait before proceeding. Some consumers who commuted more than 250 miles per day began to find that even Tesla's most robust 100 kWh battery pack simply couldn't cut it.

A newer type of battery, with lithium-sulfur cells, might address several drawbacks where a lithium-ion battery falls short. Two of the main benefits immediately noticed by researchers is the overall battery capacity and weight. A lithium-sulfur battery can hold between three and five times the energy of a lithium-ion cell, enabling the possibility of far greater trips between recharges. The batteries also have a substantially lower weight due to energy density, which could potentially allow for smaller cars like the BMW i3 to travel further without increasing the overall weight of their battery systems.

There are, however, several downsides which manufacturers will need to overcome prior to lithium-sulfur batteries becoming a viable solution in the consumer market. A batteries ages as it goes through a series of cycles of charges and discharges. As batteries age, the sulfur becomes disconnected from the battery's electrodes, which causes a rapid degradation and the battery begins to fail. A traditional lithium-ion battery cell will last between 500 and 1,500 charges, while as a lithium-sulfur cell will typically lose around 30 percent of its capacity after 100 cycles. As the battery technology matured, the industry found advancements such as polymer binders that improved stability over time, but not enough to make the batteries commercially viable.

Dr. Kyeongjae Cho, the university's professor of materials science and engineering, worked with other engineers to develop a new way to stabilize sulfur in battery cells using the metallic hardening element, molybdenum. This allowed the team to develop a battery with a higher conductivity that did not face the same fast failure rate as traditional lithium-sulfur batteries. Even if the battery life cycle is shorter when compared to a traditional lithium-ion unit, the cost of the battery packs could be greatly reduced due to the decreased cost of raw materials. Combined with the higher overall capacity, consumers may not notice a difference.

Other researchers continue to believe in the viability of solid-state batteries being the future of electric cars. Manufacturers like Fisker and Toyota are drastically improving graphene-based energy storage, which is expected to reign supreme in the future, but companies shouldn't discredit the potential for other batteries to eventually dethrone lithium-ion if advancements aren't made quickly enough elsewhere.

Car TechElectric Vehicles