Silicon–graphite (Si@G) anodes are receiving increasing attention because the incorporation of Si enables lithium-ion batteries to reach higher energy density. However, Si suffers from structure rupture due to huge volume changes (ca. 300%). The main challenge for silicon-based anodes is improving their long-term cyclabilities and enabling their charge at fast rates. In this work, we investigate the performance of Si@G composite anode, containing 30 wt.% Si, coupled with a LiNi0.8Co0.15Al0.05O2 (NCA) cathode in a pouch cell configuration. To the best of our knowledge, this is the first report on an NCA/Si@G pouch cell cycled at the 5C rate that delivers specific capacity values of 87 mAh g−1. Several techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS) and gas chromatography–mass spectrometry (GC–MS) are used to elucidate whether the electrodes and electrolyte suffer irreversible damage when a high C-rate cycling regime is applied, revealing that, in this case, electrode and electrolyte degradation is negligible.

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The significant impact of the process steps on the electrode performance is one of the least developed aspects in the field of solid‐state batteries despite being a key issue for the transference of lab‐scale developments to production scale. To demonstrate that the knowledge of production parameters is essential, a set of high active material loading solid‐state batteries with a lithium metal anode and a polymer electrolyte is fabricated using different mixing methods for the catholyte preparation. Depending on the shear rate of the mixer, the polymer molecular weight and consequently, the viscosity of the catholyte is affected and these differences are preserved during the slurry preparation and electrode coating. The electrochemical performance of each cathode is studied in full‐cell configuration obtaining high areal capacities (≈1 mAh cm−2) and high specific capacities (92%, 82%, and 95% of the theoretical capacity of LiFePO4). After 50 cycles, composite cathodes mixed with high‐shear‐rate techniques experience a capacity fade related with the larger degree of deagglomeration of the C65 occurring when less viscous catholytes are used. Low‐shear‐rate cathodes keep the starting capacity, revealing a protective role of the catholyte during the wet‐mixing process.