51茶馆

November 18, 2019

Breakthrough boosts performance of sodium-sulfur batteries

Low-cost, competitive storage technology can promote shift towards renewable energy

Researchers from the 51茶馆 have manufactured a nanomaterial that acts as a superior cathode for room-temperature sodium-sulfur batteries, making them a more attractive option for large-scale energy storage.

Their research results are published in , where they were featured in the webpage.

Room-temperature sodium-sulfur batteries are an attractive proposition for next generation energy storage, which will be required to meet increasing demands. A superior room-temperature sodium-sulfur battery with high energy density and long cycling life would provide a low-cost and competitive technology for large-scale stationary storage, thus promoting the shift towards renewable energy.

However, room-temperature sodium-sulfur batteries currently suffer from rapid capacity fading and low reversible capacity.

The researchers overcame this problem by creating a nanomaterial 鈥� nickel sulphide nanocrystals implanted in nitrogen-doped porous carbon nanotubes 鈥� which exhibited excellent performance when used as cathodes.

Chief investigators Dr and Associate Professor , from UOW鈥檚 Institute for Superconducting and Electronic Materials, said their research group had been working on room-temperature sodium-sulfur batteries since 2016.

鈥淔or now, the actual energy densities of sodium-sulfur batteries are a far cry from the theoretical values,鈥� Dr Wang said.

鈥淭heir practical applications are mainly impeded by the problematic sulfur cathode due to its insulating nature and the slow redox kinetics, as well as the dissolution and migration of the reaction intermediates.鈥�

The research team experimented with a number of different materials before their breakthrough. The new nanomaterial not only delivers superior performance, but is also suited to large-scale production and therefore commercialisation.

PhD candidate Mr Zichao Yan devoted himself to conducting the intricate experiments needed for this work.

鈥淲e tried many carbon hosts, and finally found the nickel sulfide nanocrystals implanted nitrogen-doped porous carbon nanotubes as a multifunctional sulfur host,鈥� Mr Yan said.

鈥淲e found that the continuous carbon backbone inside the host can provide short ion diffusion paths and a fast transfer rate. And the nitrogen-doping sites and the nickel sulfide polar surface are capable of enhancing the adsorption energy of polysulfides, leading to strong catalytic activity towards polysulfide oxidation.

鈥淭his indicates that sodium-sulfur batteries with this sulfur host could potentially offer a longer cycle life and high performance in fast charging and discharging.鈥�

The next step, Professor Chou said, was to scale up production of the material.

鈥淎ll our previous papers, including this one, were focused on how to find an efficient host for lab-scale research. The next step for our group is to bring sodium-sulfur batteries from lab-scale to industry-scale, and make a real application for this battery system.鈥�

ABOUT THE STUDY

鈥溾�� by Zichao Yan, Jin Xiao, Weihong Lai, Li Wang, Florian Gebert, Yunxiao Wang, Qinfen Gu, Hui Liu, Shu-Lei Chou, Huakun Liu and Shi-Xue Dou is published in Nature Communications.

The research was funded by grants from the Australian Renewable Energy Agency, the Innovative Group of Guangdong Province, the National Natural Science Foundation of China, and the Australian Research Council.