Sodium-ion batteries: A reality that is getting closer every day
In the current context of the energy crisis, it is necessary to develop renewable energies and systems capable of storing this energy, including batteries. In addition, most portable electronic devices and electric vehicles use lithium-ion batteries due to their excellent properties. However, lithium is expensive, scarce and only found in a few countries in the world. Therefore, the efforts of the scientific community have focused on discovering alternatives to lithium-ion batteries, such as sodium-ion batteries.
Sodium-ion batteries are much cheaper because sodium is a very abundant element that is homogeneously distributed throughout the Earth’s crust. Due to the similarity between sodium and lithium, materials and components from one technology have been directly transferred to the other. However, differences in size and chemical behaviour between these two elements require the development of specific materials to enable the deployment of sodium-ion batteries.
For example, so-called hard carbons, which can be obtained from plant waste, have been found to be better anode materials than the graphite used in lithium-ion batteries. However, there is still room for improvement in the amount of energy they are capable of storing.
In this context, the research team of the Instituto de Nanociencia y Materiales de Aragón, INMA, a joint institute of the CSIC and the University of Zaragoza, formed by María Bernechea Navarro, ARAID Researcher at the University of Zaragoza at INMA, M. Pilar Lobera González, Associate Professor at the University of Zaragoza at INMA and Sergio Aina Sanz,, Predoctoral Researcher at the University of Zaragoza at INMA, in collaboration with researchers from the National Institute of Chemistry, NIC, in Slovenia, have developed new methodologies to improve the behaviour of carbons used as anodes in sodium ion batteries.
Carbon-nanoparticle hybrid materials
On the one hand, it has been described how the incorporation of bismuth sulphide nanoparticles into hard carbons increases the amount of energy that the electrode can store. Using advanced characterisation techniques (including operando techniques, which allow real-time observation of structural changes in the material, during the charging and discharging of the device), it has been shown that the increase in storage capacity is due to chemical reactions between the bismuth in the nanoparticles and the sodium. This strategy opens up the possibility of improving the anodes of these batteries by adding different nanoparticles capable of interacting with the sodium ion.
Surface treatments for carbons
On the other hand, treating hard carbons with small organic molecules at room temperature has been found to be a quick, simple and inexpensive way to improve their performance as anodes in sodium ion batteries. The addition of these molecules allows the pore size of the carbons to be controlled, facilitating facilitating the reversible entry and exit of the sodium ions. This method could also be of interest in other areas where carbonaceous materials are used, e.g. adsorption of pollutants or electrocatalysis. Furthermore, depending on the functional groups present in the organic molecules, the composition of the interface between the electrode and the electrolyte can be controlled. This interface is critical for battery performance and lifetime; for example, it can be improved with molecules that have thiol groups in their composition.
This work has been funded by the M-ERA.NET network (NOEL project: Innovative Nanostructured Electrodes for Energy Storage Concepts) through MCIN/AEI/10.13039/501100011033 (Ref: PCI2019-10363), the MCIN funded by the European Union with NextGenerationEU funds promoted by the Government of Aragon (Ref: PRTR-C17.I1) and the Government of Aragon (Call for pre-doctoral contracts 2023-2027).
Links to the publications:
“Exploring hybrid hard carbon/Bi2S3-based negative electrodes for Na-ion batteries”: https://doi.org/10.1039/D4GC00564C
“Simple surface treatment improves performance of carbon materials for sodium ion battery anodes”: https://doi.org/10.1016/j.jpowsour.2024.234730
Images:
Figure 1: Sodium ion button cells manufactured at INMA.
Figura 2: Research team at the Instituto de Nanociencia y Materiales de Aragón, INMA, a joint institute of CSIC and the University of Zaragoza. From left to right: M. Pilar Lobera González, Professor at the University of Zaragoza at INMA, Sergio Aina Sanz, Predoctoral Researcher at the University of Zaragoza at INMA and María Bernechea Navarro, ARAID Researcher at the University of Zaragoza at INMA
24-05-2024
