Material Design, Characterization and Synthesis at the Highest Level

Research Division: Materials
© MEET/Judith Kraft

A key role in developing existing and new sustainable batteries of the future is played by the materials used. These materials determine important features of batteries such as energy density, performance, service life, safety, costs and sustainability. Our researchers working in this field develop new battery materials and optimize existing ones. The aim is to improve energy storage systems, adapting them precisely for the use to which they will be put, or to open up new areas of use. Also, the team decodes complex mechanisms in the materials in the battery cells – which is the precondition for developing a better understanding of the processes and reactions taking place. In its work, the team can draw on wide-ranging experience, especially in the development and synthesis of electrochemical energy storage materials. It has already been granted numerous patents, relating for example to electrolyt additives.

Innovative Materials for Inexpensive and Sustainable Batteries of the Future

It is lithium-ion batteries which dominate the market nowadays. Light, compact and with an unprecedented energy and power density, this is currently a successful technology – and one which will also play a decisive part in energy storage in the future. A battery system which could soon provide a widespread substitute for lithium-ion batteries is not yet in sight. This makes it all the more important – and more challenging – to continue developing, and to optimize, existing technology and the materials it uses. After all, the expectations that people will have in the future are high, especially as regards electromobility and stationary storage solutions. Lithium-ion batteries need to become ever more efficient, cost-effective, and sustainable.

Scanning electron microscopy image of synthesized Ni0.8Co0.1Mn0.1O2 (NCM811) cathode particle

For this to succeed, our team in the materials department concentrates its research work on active storage materials for the positive and negative electrodes in lithium-ion batteries. These active materials have the greatest influence on the characteristics of the battery cell and so they provide researchers with a crucial starting point for their work. An important role is also played by the work carried out on inactive materials in battery electrodes such as binders, electrical conductors or electrically conductive carbon black. A further component is research on materials for alternative energy storage systems apart from lithium-ion technology. Here, with its work on dual-ion batteries (where our researchers hold two basic patents), the MEET team is among the leading groups worldwide working in this field.

The expectations that people will have in the future are high, especially as regards electromobility and stationary storage solutions. Lithium-ion batteries need to become ever more efficient, cost-effective, and sustainable.
Dr. Tobias Placke, Division Manager Materials at MEET
  • From Basic Research to Applications

    Our researchers have a wide range of competencies enabling them to undertake a systematic physical and chemical characterization of battery materials. At MEET, there are several methods available for examining battery materials, electrodes or cells:

    • ex situ and post mortem – outside the cell and after use
    • in situ – in the cell itself, and
    • in operando – while the cell is being used under operating conditions very similar to those found in practice.

    Some of the approaches used are, for example, measurements by means of scanning electron microscopy, ex situ and in situ X-ray powder diffractometry XRD, in situ raman and infrared spectroscopy, or in situ dilatometry. Research work is also done on the combination or new development of suitable analytical methods.

    © MEET/Judith Kraft

    As regards efficient, cost-effective, and sustainable energy storage systems, the international team in the materials department undertakes basic research as well as looking at applications-oriented questions. Examples of this basic research are the development of optimized materials and electrolytes or electrolyte additives to stabilize electrode/electrolyte interfaces and intermediate phases. The research findings obtained in this connection include fundamental insights resulting from systematic analytical work on these interfaces and on ageing effects occurring in the intermediate phases.

    One very clear focus of our competence in materials research is on the synthesis of new types of storage materials, using a broad range of methods. The researchers use precipitation syntheses, for example – including the use of a Couette-Taylor-Flow Reactor – hydrothermal syntheses, ball mill syntheses, carbonization or graphitization methods – including the use of a graphitization or rotary kiln – and the production of thin films by means of magnetron sputtering deposition.

  • Operating principle of the Couette-Taylor-Flow Reactor
    © WWU/MEET

    Examples of High Practical Relevance

    The high degree of practical relevance shown by the research work carried out at MEET has already been repeatedly demonstrated, for example in the form of numerous patents, publications and conference papers. The team has wide-ranging competencies in the systematic production and comprehensive characterization of anode and cathode materials for lithium-ion batteries with commercially relevant particle properties. Specific examples are the production of silicon materials with optimized particle properties and good performance in full cells or the production of cathode materials using a Couette-Taylor-Flow Reactor.