Beyond Li-ion Batteries: Novel, Efficient Electrode Materials for Sodium Ion Storage

• Applicant: Dr. Magdalena Graczyk-Zajac
• Subject Area: Synthesis and Properties of Functional Materials
• Term: from 2019 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 426530815

There is an urgent need to develop a highly efficient, low-cost alternative to the now ubiquitous lithium-ion batteries. The lack of high-performing electrode materials is the main challenge in introducing a new technology to the market, which can be by far more cost-effective than Li-ion-based electrodes. 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 be reliably 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. The proposed cooperation generates enormous benefits for the partners, and none of the teams can alone achieve the project objectives.

• DFG Programme: Research Grants
• International Connection: Poland
• Partner Organisation: Narodowe Centrum Nauki (NCN)
• Cooperation Partner: Dr.-Ing. Monika Wilamowska-Zawlocka
• Co-Investigator: Professor Ralf Riedel