The quest for inexpensive and reliable grid-scale energy storage has taken a promising turn, with Stanford researchers announcing they’ve come up with a new electrode material that can withstand 40,000 charging and discharging cycles – about 100 times what the average lithium-ion battery can take.
“That is a breakthrough performance,” said Yi Cui, a Stanford professor who advised grad student Colin Wessells in his research and was coauthor on their paper, with colleague Robert Huggins, published recently in the journal Nature Communications. The key to the electrode’s durability, the researchers said, is the atomic structure of the nanomaterial used to make it: crystalline copper hexacyanoferrate.
“The crystals have an open framework that allows ions – electrically charged particles whose movements en masse either charge or discharge a battery – to easily go in and out without damaging the electrode. Most batteries fail because of accumulated damage to an electrode’s crystal structure,” the university said.
But there is a little hurdle left for the Stanford researchers to overcome.
“The sole significant limitation to the new electrode is that its chemical properties cause it to be usable only as a high voltage electrode,” the university said. “But every battery needs two electrodes – a high voltage cathode and a low voltage anode – in order to create the voltage difference that produces electricity. The researchers need to find another material to use for the anode before they can build an actual battery.”
The good news: The researchers said they already have “promising candidates” to complete a battery that by using a water-based electrolyte and electric materials that are far less expensive than lithium, could be economically viable for energy storage for wind or solar power plants.