Incorporating an industrial by-product into lithium-sulphur batteries could increase the driving range and cut the price of electric vehicle batteries, according to a new study by the University of British Columbia (UBC) researchers. An article on the UBC research was published by PICS Pacific Institute For Climate Control.
The research said that tellurium, a by-product of the copper and lead-zinc smelting process, has 30 times the electrical conductivity of sulphur, which is itself emerging as a promising component of next-generation batteries due to its ability to support high energy density, despite its limitations as an electrical conductor. Â
The report said that a compound that combines sulphur and tellurium could overcome those limitations, said the lead researcher, assistant professor Jian Liu. “People have been looking into sulphur batteries for many years, but it is challenging to commercialize because sulphur doesn’t transport electrons at all,” said Liu. “We are looking for a way to balance electronic conductivity with energy density as a way to make lithium-sulphur batteries viable.” “Finding that compound is our next step,” he said.
The study – Materials Design and Fundamental Understanding of Tellurium-based Electrochemistry for Rechargeable Batteries – published in the journal Energy Storage Materials– notes tellurium’s high volumetric capacity, which could enable greater storage capacity and faster charging and discharging than existing rechargeable lithium-ion batteries. The reports said: “Solid state tellurium-based batteries could be safer than conventional EV batteries, which employ flammable liquid electrolytes.Â
The researchers note that significant limitations must be overcome, including tellurium’s tendency to expand and contract leading it to pulverize other active materials where they are combined. The researchers believe that problem can be overcome by creating a stable compound combining sulphur, tellurium, and carbon. While tellurium is relatively rare in the Earth’s crust it can be recovered during metals production and Liu is confident that tellurium can also be recovered from end-of-service tellurium batteries and used again.
Since lithium-ion batteries changed the world over 30 years ago the need for a safer, lighter, longer lasting battery has been the challenge, it seems that tellurium may be the answer. Current lithium-ion batteries use sulfur and selenium as electrode materials, tellurium is a better conductor with higher energy density.
Singapore’s Agency for Science, Technology and Research (A*STAR) researchers have demonstrated that electrodes made from tellurium can improve the energy storage and power output of rechargeable lithium-ion batteries. Tellurium electrodes have higher energy densities and may be charged and discharged faster than conventional electrode materials.
The team then developed a cathode made entirely from tellurium nanowires just seven nanometers wide, which they laid together to form a mat. This formed a flexible tellurium cathode with an energy density of 1800 milliwatt hours per cubic centimeter which allowed it to store 50 per cent more energy than a conventional lithium cobalt oxide electrode of the same size. It also retained more than 98 per cent of its capacity after 80 charging cycles.
Not only is tellurium showing vast improvements in current lithium-ion batteries but in metal tellurium batteries, sulphur tellurium, zinc tellurium and new solid state lithium batteries as well.
A research team at The University of Texas at Austin has found a way to stabilize lithium-sulfur batteries, making them more likely to become commercially viable.
Lithium-sulfur batteries deliver more use per charge and are environmentally friendlier, but degrade quickly over time. Both the positive and negative electrodes in lithium-sulfur batteries hold 10 times as much charge capacity as materials in today’s lithium-ion batteries. Coating the lithium electrode with tellurium protects the electrolyte from degrading, stunts the growth of deposits and lets the battery last longer. The added a layer of tellurium on top of the lithium metal inside the battery extends the battery’s lifespan by a factor of four compared to other lithium batteries.
