Li-ion battery inventor announces solid-state breakthrough
Image credit: The University of Texas at Austin
A team led by 94-year old John Goodenough, one of the inventors of lithium-ion batteries, has developed an all-solid-state battery cell that is low-cost while offering a long life cycle, high energy density and fast charge and discharge rates.
Goodenough, a Professor of engineering at the University of Texas at Austin, said the new battery could solve some of the major drawbacks of today’s commercially available lithium-ion batteries.
“Cost, safety, energy density, rates of charge and discharge and cycle life are critical for battery-driven cars to be more widely adopted,” Goodenough commented.
“We believe our discovery solves many of the problems that are inherent in today’s batteries.”
The non-combustible battery, described in the journal Energy & Environmental Science, has an energy density at least three times that of today’s lithium-ion batteries. A battery cell’s energy density gives an electric vehicle its driving range, so a higher energy density means that a car can drive more miles between charges. The UT Austin battery formulation also allows for a greater number of charging and discharging cycles, which equates to longer-lasting batteries. The researchers said the battery can be recharged within minutes instead of hours, which is typical for today’s batteries.
Today’s batteries rely on liquid electrolytes to transport ions between the anode and the cathode. If a battery cell is charged too quickly, it can cause dendrites or ‘metal whiskers’ to form and cross through the liquid electrolytes, creating a short circuit that can lead to explosions and fires.
The new battery developed by Goodenough and senior research fellow Maria Helena Braga uses glass-based electrolytes and an alkali-metal anode. This combination doesn’t lead to the creation of dendrites and thus mitigates the short-circuit hazard.
“The glass electrolytes allow for the substitution of low-cost sodium for lithium. Sodium is extracted from seawater that is widely available,” explained Braga, adding that as a result, the new battery is much more environmentally friendly than current lithium-ion batteries.
Alkali-metal anodes consisting of lithium, sodium or potassium can’t be used in conventional batteries. The use of this technology, however, provides the battery with an increased energy density and longer life-cycle.
The solid-glass electrolytes can operate in extremely cold temperatures, down to -20°C. Earlier solid-state batteries were unable to operate at temperatures lower than 60°C – a major obstacle for practical use.
Braga began developing solid-glass electrolytes with colleagues while she was at the University of Porto in Portugal. About two years ago, she began collaborating with Goodenough and researcher Andrew J Murchison at UT Austin.
Braga said that Goodenough brought an understanding of the composition and properties of the solid-glass electrolytes that resulted in a new version of the electrolytes that is now patented through the UT Austin Office of Technology Commercialization.
The engineers’ glass electrolytes allow them to plate and strip alkali metals on both the cathode and the anode side without dendrites, which simplifies battery cell fabrication.
Goodenough and Braga are continuing to advance their battery-related research and are working on several patents. In the short term, they hope to work with battery makers to develop and test their new materials in electric vehicles and energy storage devices.