## Results  
### Electrode Preparation  
NMC 622 cathodes were tape-casted with thicknesses from 140 \(\upmu\)m to 320 \(\upmu\)m by adjusting the gap between doctor blade and Al foil. For cathode films with thickness over 200 \(\upmu\)m, less NMP solvent was added during the second mixing step, in order to achieve a slurry with higher viscosity (3-4 Pa-s at the shear rate of 50 s\({}^{-1}\)). The porosity of a dried cathode was determined by the following equation [7]:  
\[Porosity=\frac{V-(\frac{m_{NMC}}{p_{NMC}}+\frac{m_{TIMACAL}}{p_{TIMACAL}}+\frac {m_{PVDE}}{p_{PVDE}})}{V}=\frac{H-M_{total}\cdot\sum_{i}\frac{c_{i}}{p_{i}}}{H}, \tag{1}\]  
where \(V\) is the maximum possible volume, taking into account the outer dimensions of the composite electrode, \(m\) is the mass of each component, and \(\rho\) is the density of each component. Since there are only three components of a cathode, \(m\) can be replaced by the total mass multiplying the content percentage (c\({}_{i}\)) of each component. In addition, the cathodes were laser-cut in circles of 12 mm in diameter. It is convenient to substitute mass with areal mass \(M\) (g/cm\({}^{2}\)). \(H\) is the thickness of the cathode without aluminum current collector. The thickness, porosity, and other details of cathode films are listed in Table 1.  
The mass loading in Table 1 is defined as the mass of active material (NMC 622) divided by the electrode area. The state of the art electrodes with thicknesses from 50 to 100 \(\upmu\)m have mass loadings of 10-20 mg/cm\({}^{2}\). However, in this paper, the mass loadings of the cathodes were increased to over 50  mg/cm\({}^{2}\). Figure 2 shows the cross-section of laser structured NMC 622-cathodes with thicknesses of 111 \(\upmu\)m, 171 \(\upmu\)m, and 270 \(\upmu\)m and generated grooves with aspect ratios of 1:3, 1:5.5, and 1:8, respectively. The width of the groove structures of electrodes with thicknesses of 111 \(\upmu\)m, 171 \(\upmu\)m, and 270 \(\upmu\)m for their cathodes were 33 \(\pm\) 5 \(\upmu\)m, 28 \(\pm\) 5 \(\upmu\)m, and 32 \(\pm\) 5 \(\upmu\)m, respectively. The sidewalls of the channels showed a slight curvature, which became more obvious for thin film electrodes. The rugged edges of the structures may due to the inhomogeneity of electrode materials inside the thick film. The active mass loading of each cathode was measured from electrodes with a diameter of 12 mm. For unstructured cathodes, the mass loading increased with increasing film thickness from 21.7 mg/cm\({}^{2}\) to 56.7 mg/cm\({}^{2}\), while for the laser structured cathodes, the mass loading increased with increasing \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Pitch Distance** & **Thickness as** & **Thickness after** & **Final Thickness without Al foil** & **Porosity (\%)** & **Active Mass Loading (mg/cm\({}^{2}\))** & **Mass Loss (\%)** \\ \hline unstructured & 141 \(\pm\) 1 & 111 \(\pm\) 3 & 91 & 36.1 & 21.7 \(\pm\) 0.1 & - \\
200 & 141 \(\pm\) 1 & 111 \(\pm\) 3 & 91 & - & 18.5 \(\pm\) 0.3 & 14.1 \(\pm\) 1.0 \\
400 & 141 \(\pm\) 1 & 111 \(\pm\) 3 & 91 & - & 20.3 \(\pm\) 0.2 & 6.6 \(\pm\) 0.9 \\
600 & 141 \(\pm\) 1 & 111 \(\pm\) 3 & 91 & - & 21.0 \(\pm\) 0.2 & 3.4 \(\pm\) 0.9 \\ unstructured & 201 \(\pm\) 2 & 171 \(\pm\) 3 & 151 & 36.7 & 33.8 \(\pm\) 0.2 & - \\
200 & 201 \(\pm\) 2 & 171 \(\pm\) 3 & 151 & - & 31.2 \(\pm\) 0.5 & 7.7 \(\pm\) 1.9 \\
400 & 201 \(\pm\) 2 & 171 \(\pm\) 3 & 151 & - & 32.2 \(\pm\) 0.7 & 4.7 \(\pm\) 1.7 \\
600 & 201 \(\pm\) 2 & 171 \(\pm\) 3 & 151 & - & 32.7 \(\pm\) 0.4 & 3.3 \(\pm\) 1.4 \\ unstructured & 305 \(\pm\) 2 & 270 \(\pm\) 4 & 250 & 36.0 & 56.7 \(\pm\) 0.2 & - \\
200 & 305 \(\pm\) 2 & 270 \(\pm\) 4 & 250 & - & 51.7 \(\pm\) 0.2 & 8.8 \(\pm\) 2.1 \\
400 & 305 \(\pm\) 2 & 270 \(\pm\) 4 & 250 & - & 54.2 \(\pm\) 1.0 & 4.4 \(\pm\) 1.9 \\
600 & 305 \(\pm\) 2 & 270 \(\pm\) 4 & 250 & - & 54.7 \(\pm\) 0.8 & 3.5 \(\pm\) 1.9 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Parameters of Li(Ni\({}_{0.6}\)Mn\({}_{0.2}\)Co\({}_{0.2}\))O\({}_{2}\) (NMC 622) cathodes. pitch distance.