BeschreibungA straight-forward way of maximizing the energy density of Li-ion batteries is to increase the thickness of assembled electrodes. Unfortunately, establishing thick coatings with homogenously distributed material components and sufficient mechanical stability brings an extra level of complexity to the manufacturing process. Especially drying parameters must be selected carefully to minimize binder migration within the coating. High concentrations of binder material at the top of the electrode can have blocking effects on Li-ion transport pathways and additionally cause delamination of the layer from the substrate foil. Performing multiple coatings on top of each other has proven beneficial for thick electrode fabrication: The evolution of major defects can be suppressed, and further processing is facilitated due to an increase of adhesion to the current collector foil. Additionally, multi-layer coating creates numerous possibilities to establish 3D-like architectures within the electrode for example by introducing material gradients. We recently demonstrated that cells with multi-layered cathodes outperform conventionally manufactured cells at rate capability tests. Also, the adhesion strength of the coating was improved by 40%, following the multi-layering method. In this work, Ni-rich lithium nickel manganese cobalt oxide (NMC811) was used as active material to produce multi-layered electrodes. Binder concentrations in the top layer were reduced in multiple steps. Investigations on mechanical integrity and electrochemical performance were conducted for water-processed cathodes of high areal loading (> 8 mAhcm-2) at full cell level. Decreasing the amount of binder showed beneficial results during rate capability test and long-term cycling. An increase of up to 40% in specific discharge capacity was achieved compared to conventionally prepared electrodes at 1C.
|6 Nov. 2022 → 8 Nov. 2022
|International Battery Production Conference 2022
- Sustainable and Smart Battery Manufacturing