Most modern devices, from mobile devices to car batteries, use lithium-ion batteries. It’s the best proven solution out there currently, but it’s far from perfect. As electric vehicle and mobile device technology improve, a search is on for a battery that can be even more effective than lithium-ion technology but without the drawbacks. A team of Swiss scientists at École Polytechnique Fédérale de Lausanne (EPFL) might have made a major step towards finding it.
One such material being explored is sodium. Sodium exists in far greater quantities than lithium, and has a fraction of its flammability. Sodium-ion batteries are being seriously looked at, but since sodium is considerably less energy-dense than lithium, sodium-ion batteries would have to be larger to get the same amount of energy. Battery size is a common dealbreaker for modern electronics.
Lithium-ion batteries use graphite electrodes, which don’t play well with sodium particles. The team replaced graphite with graphene, “doping” the material with sodium, using liquid ammonia as a catalyst agent. The resulting material was a multi-layered graphene sheet rich in sodium.
“Lithium is becoming a critical material as it is used extensively in cell-phones and car batteries, while, in principle, sodium could be a much cheaper, more abundant alternative,” said Ferenc Simon, a visiting scientist at EPFL. “This motivated our quest for a new battery architecture: sodium doped graphene.”