Scientists use neat chemistry tricks to tackle the big challenges facing future batteries. Their breakthrough paves the way for next-generation electric vehicle (EV) batteries that can power a 500-mile (800km) journey on a single 12-minute charge.
Lithium metal batteries differ from standard lithium-ion batteries in that the graphite anode is replaced by lithium metal. These designs provide much higher energy densities, researchers said in a statement.
For EV drivers, this means a battery that charges faster and moves even more. However, scientists were unable to build effective lithium metal batteries due to “dendrites.” This is a branched crystalline material that grows at the anode during charging, which erodes the performance of the battery over time. This can worsen during quick charging and increase the risk of a battery short-circuiting.
You might like it
However, in a new study published in Nature Energy on September 3, scientists found a way to stop dendritic growth.
The secret lies in a new type of liquid electrolyte. Liquid electrolytes that “inhibit aggregation” suppress dendrite growth, increase the battery’s rapid charging capacity, and extend its lifespan to over 185,000 miles (300,000 km), researchers said.
Related: Meet Chinese supercars that just broke their EV speed records
Both lithium ions and lithium metal batteries contain liquid electrolytes, which transport lithium ions between the cathode and anode during charging and discharging. As mentioned above, the difference between the two types of batteries is that the graphite in the lithium-ion battery is replaced by lithium metal.
In battery physics, energy density refers to the amount of energy a battery can store relative to its weight or volume. This is a key factor in how much an electric vehicle can travel on a single charge.
The researchers found that the underlying cause of dendrite formation was “non-uniform interfacial cohesion on the surface of lithium metal,” the researchers said in a statement. In other words, they noticed that lithium ions do not evenly accumulate throughout the anode during charging, creating a weakness that allows dendrites to begin to form.
To solve this problem, they develop chemically structured liquid electrolytes to ensure that ions are deposited more evenly throughout the anode surface, helping to stop clustering into the dendrites.
In lab testing, the battery was charged from 5% to 70% in 12 minutes, maintaining speeds of over 350 cycles. Scientists say that in 17 minutes, the 80% capacity version reached 80% charge over 180 charging cycles.
“This research is an important foundation for overcoming the technical challenges of lithium metal batteries by understanding interface structure,” said Hee Tak Kim, professor of chemistry and biomolecular engineering at the Korea Institute of Advanced Technology (KAIST), in a statement.
“It overcame the biggest barrier to the introduction of lithium metal batteries for electric vehicles.”
Source link
