Beyond Li-Ion Batteries: Novel Efficient Electrode Materials for Sodium Ion Storage (BLESS)

Project in a frame of Beethoven Classic 3, Polish-German Funding Initiative granted by the Polish National Science Centre (NCN) and Deutsche Forschungsgemeinschaft (DFG, German Research Foundation), 2020-2023.


Dr. Ing. Monika Wilamowska, Dr. Ing. Andrzej Nowak, Gdansk University of Technology (PL)

Dr. Grzegorz Trykowski, Nicolaus Copernicus University of Torun (PL)

This project aims to develop, investigate and characterise novel, stable and cost-efficient electrodes for Na-ion battery (NIB). The key to rationalise the electrochemical performance of battery materials is to determine the ion storage host and to define the local structure and microstructural stability of the material. In parallel, the ionic transport must bereliably assessed in order to predict the rate performance of the electrode.

The systematic study proposed in this project (BLESS) starts with the synthesis of novel cathode and anode materials with improved electrical conductivity and enhanced electrochemical stability. The cathode will consist of sol-gel derived Na3V2(PO4)3/carbon nanocomposite with varying carbon content. The novel route of Pickering emulsion assisted sol-gel synthesis will ensure the homogeneity of the composite resulting in enhanced electron transport across the electrode. “One-pot” in-situ synthesis of porous tin anode embedded in a conductive carbon and stabilised in a ceramic matrix (Sn/C/SiOC) will allow to accommodate the volume changes of tin preserving its high Na-storage capacity.

The electrical and microstructural properties of the electrode materials will be analysed by electrochemical impedance spectroscopy (EIS), 23Na solid state MAS NMR spectroscopy, and electron microscopy (SEM/TEM). The intrinsic Na-diffusion properties of the active material solely will be assessed by means of a single-particle measurement (SPM) developed within this project. The low-resistance cathode composite will allow for enhancement of the rate capability of Na-based cells. By revealing the structural changes and the ion mobility of the electrode materials, MAS NMR spectroscopy can help to deeply understand the chemistry behind the electrochemical processes and therefore improve the battery performance. Electron microscopy will allow to get insights into the structure of composite electrode materials as well as the arrangement of carbonaceous materials creating inner and outer coating of the composite.

Developing new, compatible, high capacity electrode materials for NIB in line with recognising and proposing the efficient solutions to counteract their drawbacks will be a milestone for the further development and potential application of stable sodium ion batteries.

The knowledge and experience in materials engineering and electrochemistry, as well as access to highly specialised equipment (TEM, MAS-NMR, SPM), is required for the successful realisation of the planned studies within BLESS. Here, we combine the expertises of the German partner (TUDa) in the field of materials synthesis and engineering related to novel and stable Sn/C/SiOC anode material for NIB with the experience of two Polish teams in material synthesis and analytical electrochemistry focussed on novel composite Na3V2(PO4)3/C cathode for NIB and charge transfer characterisation (Gdansk University of Technology) as well as in the field of determination of Na-storage host and microstructural stability (Nikolaus Copernicus University, Torun). The proposed cooperation generates enormous benefits for the partners, and none of the teams can alone achieve the project objectives.

M. Sc. Alexander Kempf

Supervisors: Ralf Riedel, Magdalena Graczyk-Zajac

The renewable energy sources are in principle inexhaustible but operate intermittently, thus interest in energy storage technologies for grid stabilization is growing. . This issue can be tackled by the use of stationary storage systems to enable a continuous, stable supply of electricity at any time. Sodium ion batteries (SIBs) are a promising candidate for stationary energy storage systems, offering a significant reduction of critical materials, reducing supply risks, restrictions and environmental impact, which are instead currently affecting other technologies, i.e. Lithium-ion batteries. Nevertheless there is still an ongoing research for innovative materials to improve the battery performance.

The aim of this PhD project is to prepare a tin-based anode material, which employs an alloying process for charge storing. Alloy-based anodes provide high theoretical capacities, but the charging process is accompanied by an increase in volume, which can lead to rapid capacity fading due to pulverization of the material. Within this work porous tin will be prepared in-situ and directly embedded in a conductive carbon network. Carbon coated tin will be homogeneously distributed within a polymer derived silicon oxycarbide (SiOC) ceramic matrix to further stabilize the material and allow to accommodate the volume changes of tin preserving its high Na-storage capacity.

The goal is the improvement of the electrochemical properties of the material via tuning the microstructure. This is done by adjusting the carbon and tin contents and applying different temperature conditions.