Project DialySorb - Carbons as anodes in sodium-ion batteries

05/10/2021

• Challenge
• Objectives
• Methods
• Partners

The aim is to develop batteries with high energy density based on sustainable, resource-saving materials. Since the crystalline carbon graphite cannot be used for NIBs, disordered carbons are considered particularly promising. However, these are currently not efficient enough. A tailor-made carbon composite material, which is being developed in the project, is intended to provide a remedy.The project will develop customised carbon materials as a negative electrode ("anode material") for sodium-ion batteries (NIBs).

In todays explored materials for the negative electrode, storage capacity and loss reactions are dependent on each other. Electrodes with high capacity are showing substantial losses. Electrodes that are stable, however, usually have low capacity. In DialySorb, these properties are assigned to specific material aspects and these are varied independently. New composite materials will make it possible to quantify and fully exploit the entire potential for the first time.

Large reversible capacities are to be combined with small losses. Our approach aims at a clear spatial separation of charge storage reactions and loss reactions. This shall be achieved by preparing composites with a core-shell structure. Both the core and the shell structure will be varied and the resulting effect observed. This is done for different electrolytes of the ion-conducting battery fluid involved in the side reactions.

DialySorb is a Berlin-based collaborative project funded by the BMBF with BAM as the lead institution. The collaborative partners are the Operando Battery Analysis working group at the Helmholtz Centre for Energy in Berlin (HZB), and the Chair of Functional Materials at the Technical University of Berlin. Associated industrial partners include the company Donau Carbon.

DialySorb - Molecular sieving carbons as high-capacity and stable anodes in sodium-ion batteries

DialySorb aims to develop novel, functional carbon anodes for sodium-ion batteries (NIB) with increased capacity and improved reversibility. NIBs can be operated with a similar cell chemistry as established lithium-ion batteries (LIB). The small losses in energy density are countered by improved sustainability, so that NIBs are traded as a resource-saving alternative. However, the properties of the carbon anode are considered a bottleneck of the technology, as the storage mechanism is very complex and not predictable. In addition, it is difficult to study the actual charge storage separately from side reactions, which has so far prevented a precise classification of the technology's possibilities. A Berlin-based alliance of partners with well-complementing expertise is tackling the open questions here. It is about modern carbon chemistry, the production of functional materials and advanced, process-oriented analysis.

Novel carbon anodes will be developed with the function of separating the actual storage from side reactions. At the same time, the aim is to reach higher storage capacities. The side reactions can be reduced to a minimum; this would benefit practical applications. The functional carbon anodes will be prepared with modern but also industrially relevant methods, physico-chemically characterised and tested electrochemically. In addition to advanced characterisation methods (in situ / operando), safety aspects are also taken into account.

Project coordinator

Bundesanstalt für Materialforschung und -prüfung (BAM)
Department Dangerous Goods Packagings

Project partner

Bundesanstalt für Materialforschung und -prüfung (BAM)
HZB - Helmholtz-Zentrum Berlin, Joint Research Group Operando battery analysis
TUB - TU Berlin, Department of Chemistry / Functional Materials

Funding

The DialySorb project is funded by the Federal Ministry of Education and Research (BMBF) as part of "Batterie 2020 Transfer" (funding code: 03XP0410).