Electric cars could go the extra mile thanks to new battery tech
The capacity of batteries in electric cars could be significantly increased thanks to newly developed electrodes that are stabilised in a highly-fluorinated electrolyte and have an improved energy density compared to traditional batteries.
The success of electric car batteries depends on the miles that can be driven on a single charge, but the current crop of lithium-ion batteries are reaching their natural limit in terms of how much charge can be stored in a given space.
“We have created a fluorine-based electrolyte to enable a lithium-metal anode, which is known to be notoriously unstable, and demonstrated a battery that lasts up to a thousand cycles with high capacity,” said Xiulin Fan and Long Chen, postdoctoral researchers at the University of Maryland and co-authors of a paper on the battery.
The new batteries are able to charge and discharge many times over without losing the ability to provide a reliable and high quality stream of energy.
Even after a thousand charge cycles, the fluorine enhanced electrolytes ensured 93 per cent of battery capacity, which the authors call “unprecedented”. This means that a car running on this technology would reliably drive the same number of miles for many years.
“This work is a great progress forward in the battery field in the direction of increasing the energy density, although further tuning might be needed to meet various standards for commercialisation,” said Jang Wook Choi, an associate professor in chemical and biological engineering at Seoul National University in South Korea.
The team demonstrated the batteries in a coin-cell shape like a watch battery for testing and are working with industry partners to use the electrolytes for a high-voltage battery.
These aggressive materials, such as the lithium-metal anode and nickel and high-voltage cathode materials, are called such because they react strongly with other material, meaning that they can hold a lot of energy but also tend to “eat up” any other elements they’re partnered with, rendering them unusable.
“The aim of the research was to overcome the capacity limitation that lithium-ion batteries experience. We identified that fluorine is the key ingredient that ensures these aggressive chemistries behave reversibly to yield long battery life. An additional merit of fluorine is that it makes the usually combustible electrolytes completely unable to catch fire,” said Professor Chunsheng Wang who worked on developing the electrolyte.
The team captured video of several battery cells catching on fire in instants, but the fluorine battery was impervious.
Last week researchers unveiled a salt-based battery that lasts longer than conventional batteries and stores more power.