Innovative microstructuring improves fast-charging capability of battery electrode

This innovative method for modifying the surface electrodes allows for production of fast-charging batteries with high energy density and reduced aging. Structuring is achieved by selective and exclusive removal of passive material, which significantly improves ionic transport capabilities without reducing the amount of energy that can be stored.

The properties of batteries such as energy density, power density, lifetime/aging, and safety are largely determined by the structure or microstructure of the electrodes.

The battery parameters of energy density (relevant for range and service life) and power density (relevant for (discharge) charging time) usually behave in opposite ways, which is why a compromise must be made depending on the area of application. Three-dimensional microstructuring of the electrodes, e.g. by channel formation, improves the transport properties, but is inevitably accompanied by a removal/loss of active material and thus a reduction in volumetric energy density. Therefore, it is not a satisfactory solution.

At Aalen University, an innovative method for modifying the surface of electrodes has been developed which avoids these disadvantages. The method can be used for all battery electrodes where transport processes of charge carriers via pores are rate-determining, i.e. in particular for lithium-ion batteries. For this purpose, only so-called passive material (especially binder), and not active material, is removed close to the surface of the electrode – preferably by means of a laser (IR lamp, plasma-assisted process, or similar). This significantly improves the accessibility of the electrolyte to the electrodes and consequently, the ionic transport capabilities without reducing the amount of energy that can be stored.

In addition, the stability of the electrodes is not negatively affected by the selective removal of passive material. Microstructuring can be applied to the entire electrode surface, or parts of it. It can also be applied locally by point-shaped depressions.

• higher energy density, thus more range and longer service life
• improved ionic transport, thus faster
  • charging or discharging
  • less metallic Li deposition
  • less aging
  • improved safety
• applicable especially for electrodes with high compression,
• i.e. high energy density
• applicable to a wide range of electrode materials anode- and cathode side by setting the laser parameters
• proven for lithium-ion batteries

Against the backdrop of the diverse, constantly increasing use of batteries, it has now been possible to develop an innovative method for producing surface-modified cathodes, which can increase the energy density by up to 20%. This innovative surface modification method could also be applied to graphite-based anodes of lithium-ion batteries in the future.