Batteries

Aenert. Research Laboratory news
In our daily lives, we have come to rely heavily on battery technology which plays an important role in many areas including mobile applications, electric tools and, of course, also electric vehicles. Nowadays, most of these devices rely on lithium-ion batteries which are efficient and have a wide range of possible applications. However, lithium-ion batteries also have several disadvantages ranging from short lifetimes and overheating to supply chain issues.

Now (2023), scientists at Argonne Lab Scientists at the U.S. Department of Energy’s (DOE) Argonne National Laboratory are trying to find solution to some of the pressing problems associated with common battery technology. Through testing new materials, they want to build more efficient batteries. One of the materials they tested was sulphur. This element is very abundant, inexpensive and was found to be able to hold a lot of energy into the bargain.

In their experiment, the team of researchers created an extra layer within a battery which was intended to increase the energy storage capacity and at the same time reduce a sulphur-related problem concerning the relatively quick corrosion of sulphur batteries. Their battery contained a sulfur-containing positive electrode (cathode) and a lithium metal negative electrode (anode). Between the two components there was placed the electrolyte enabling the ions to flow between the cathode and the anode.

Former battery designs were not as efficient because polysulfides invaded the electrolyte and caused corrosion which decreased the number of battery cycles. To prevent this from happening, the scientists chose to omit the previously-used ​“redox-inactive” layer which reduces the energy storage capacity and used a porous sulphur-containing interlayer instead. Tests under laboratory conditions showed that the battery had a starting capacity which was three times higher than in conventional Li-cells with an inactive layer. Also, it retained its high capacity over 700 charge-discharge cycles.

Experiments at the 17-BM beamline of Argonne’s Advanced Photon Source (APS) were also performed to thoroughly analyse the redox-active layer. This allowed them to prove that inserting an interlayer was indeed beneficial as it reduced detrimental reactions within the battery.

Image: Design rationale of redox-active ILs



Source: Byong-June Lee, Chen Zhao, Jeong-Hoon Yu, Tong-Hyun Kang, Hyean-Yeol Park, Joonhee Kang, Yongju Jung, Xiang Liu, Tianyi Li, Wenqian Xu, Xiao-Bing Zuo, Gui-Liang Xu, Khalil Amine, Jong-Sung Yu/ Development of high-energy non-aqueous lithium-sulfur batteries via redox-active interlayer strategy/ Nature Communications volume 13, Article number: 4629 (2022), 08 August 2022/ doi.org/10.1038/s41467-022-31943-8/ Open Access This is an Open Access article is distributed under the terms of the Creative Commons Attribution 4.0 International (CC BY 4.0)

Scientists have long sought to harness the potential of lithium-sulphur batteries. In 2016, several nonconductive metal-oxide nanoparticle-decorated carbon flakes were made through a facile biotemplating method. The cathodes consisting of magnesium oxide, cerium oxide and lanthanum oxide exhibited increased cycling performance. By means of adsorption experiments and theoretical calculations it was shown that polysulfide capture by the oxides took place with the help of monolayered chemisorption. Also, it was shown that better surface diffusion caused higher deposition efficiency of the sulphide species on electrodes. Therefore, oxide selection was proposed as a means to balance optimisation between sulphide-adsorption and diffusion on the oxides.

Image: Schematic of the Li₂Sx adsorption and diffusion on the surface of various nonconductive metal oxides



Source: Xinyong Tao, Jianguo Wang, Chong Liu, Haotian Wang, Hongbin Yao, Guangyuan Zheng, Zhi Wei Seh, Qiuxia Cai, Weiyang Li, Guangmin Zhou, Chenxi Zu, Yi Cui/ Balancing surface adsorption and diffusion of lithium-polysulfides on nonconductive oxides for lithium–sulfur battery design/ Nature Communications volume 7, Article number: 11203 (2016), 05 April 2016/ doi.org/10.1038/ncomms11203/ Open Access This is an Open Access article is distributed under the terms of the Creative Commons Attribution 4.0 International (CC BY 4.0)

In 2020, a method was designed where tiny amounts of a high-modulus binder were applied between neighbouring particles, thus leaving increased space for material expansion and ion diffusion. These expansion-tolerant electrodes with loadings up to 15 mg cm⁻² had high gravimetric (>1200 mA·hour g⁻¹) and areal (19 mA·hour cm⁻²) capacities. The cells showed stability for more than 200 cycles with an Coulombic efficiency above 99%.

Image: Morphological study, tomographic reconstruction, and schematic illustration of cathodes with identical composition and different slurry preparation methods



Source: Mahdokht Shaibani, Meysam Sharifzadeh Mirshekarloo, Ruhani Singh, Christopher D. Easton, M. C. Dilusha Cooray, Nicolas Eshraghi, Thomas Abendroth, Susanne Dörfler, Holger Althues, Stefan Kaskel, Anthony F. Hollenkamp, Matthew R. Hill, and Mainak Majumder/ Expansion-tolerant architectures for stable cycling of ultrahigh-loading sulfur cathodes in lithium-sulfur batteries/ Science Advances, Vol 6, Issue 1/ DOI: 10.1126/sciadv.aay2757/ Open Access This is an Open Access article is distributed under the terms of the Creative Commons Attribution NonCommercial License 4.0 (CC BY-NC)

There are several advantages associated with lithium-sulphur batteries: The redox-active layer was found to increase energy storage capacity and suppress the shuttle effect. This, in turn, can reduce adverse reactions in the battery and increase the battery’s capacity to hold more charge and last for more cycles. ​The experiments also demonstrated that a redox-active interlayer could have a huge impact on Li-S battery development.

Further research will include analysing the growth potential of the redox-active interlayer technology. Their final goal is to find a way to make this layer even thinner and lighter. So far, the research has contributed to making a huge step forward towards readying lithium-sulphur batteries for large-scale applications.

By the Editorial Board