By Mark Kane, March 2, 2017
Inside EVs -- John Goodenough, famous for co-inventing the lithium-ion battery and currently 94-year-old professor in the Cockrell School of Engineering at The University of Texas at
New solid-state battery developed by a team of engineers in
“Goodenough’s latest breakthrough, completed with Cockrell School senior research fellow Maria Helena Braga, is a low-cost all-solid-state battery that is noncombustible and has a long cycle life (battery life) with a high volumetric energy density and fast rates of charge and discharge. The engineers describe their new technology in a recent paper published in the journal Energy & Environmental Science.”
If that doesn’t sound good enough, there are also other advantages, making us wonder how fast someone will introduce these on the market:
- safer, noncombustible
- longer-lasting (demonstrated more than 1,200 cycles with low cell resistance)
- could perform well in subzero degree weather, first all-solid-state battery cell that can operate under 60 degree Celsius
- cells can be made from earth-friendly materials
“Cost, safety, energy density, rates of charge and discharge and cycle life are critical for battery-driven cars to be more widely adopted. We believe our discovery solves many of the problems that are inherent in today’s batteries,” Goodenough said.
The researchers demonstrated that their new battery cells have at least three times as much energy density as 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, as well as a faster rate of recharge (minutes rather than hours).
Today’s lithium-ion batteries use liquid electrolytes to transport the lithium ions between the anode (the negative side of the battery) and the cathode (the positive side of the battery). If a battery cell is charged too quickly, it can cause dendrites or “metal whiskers” to form and cross through the liquid electrolytes, causing a short circuit that can lead to explosions and fires. Instead of liquid electrolytes, the researchers rely on glass electrolytes that enable the use of an alkali-metal anode without the formation of dendrites.
The use of an alkali-metal anode (lithium, sodium or potassium) — which isn’t possible with conventional batteries — increases the energy density of a cathode and delivers a long cycle life. In experiments, the researchers’ cells have demonstrated more than 1,200 cycles with low cell resistance.
Additionally, because the solid-glass electrolytes can operate, or have high conductivity, at -20 degrees Celsius, this type of battery in a car could perform well in subzero degree weather. This is the first all-solid-state battery cell that can operate under 60 degree Celsius.
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.
Another advantage is that the battery cells can be made from earth-friendly materials.
“The glass electrolytes allow for the substitution of low-cost sodium for lithium. Sodium is extracted from seawater that is widely available,”