New Research published in the ACS journal Nano Letters describes a powdery nanomaterial that can extend the lifespan of lithium-sulphur batteries. These batteries are used in electric vehicles and this substance has the power to extend their battery life and thus the range (distance an electric vehicle can travel on a single charge).
The nanomaterial which is being called a metal organic framework is added to the battery’s cathode to capture problematic polysulfides that usually cause lithium-sulfur batteries to fail after a few charges.
“Lithium-sulphur batteries have the potential to power tomorrow’s electric vehicles, but they need to last longer after each charge and be able to be repeatedly recharged,” said materials chemist Jie Xiao of the US Department of Energy’s Pacific Northwest National Laboratory (PNNL).
“Our metal organic framework may offer a new way to make that happen,” Xiao said.
Electric vehicle owners are typically conscious of far they can drive before the charge runs out thus limiting the spread and sale of electric vehicles. But this new battery can be a game changer as it can offer four times more energy per mass than lithium-ion batteries. But there is a negative aspect too. The lithium-sulphur batteries have a much lower life cycle and cannot be recharged as many times as a lithium-ion battery. The next level of research would thus need to increase the life span to make such an idea commercially sustainable.
“The MOF’s highly porous structure is a plus that further holds the polysulfide tight and makes it stay within the cathode,” said PNNL electrochemist Jianming Zheng.
During lab tests, a lithium-sulphur battery with PNNL’s MOF cathode maintained 89 per cent of its initial power capacity after 100 charge-and discharge cycles.
Jianming Zheng, Jian Tian, Dangxin Wu, Meng Gu, Wu Xu, Chongmin Wang, Fei Gao, Mark H. Engelhard, Ji-Guang Zhang, Jun Liu & Jie Xiao, “Lewis Acid-Base Interactions Between Polysulfides and Metal Organic Framework in Lithium Sulfur Batteries,” Nano Letters, published online April 4, 2014, DOI: 10.1021/nl404721h