Solid-state batteries (SSBs) provide a promising technical solution to meet the key requirements of future energy storage systems, i.e., safety and high energy density, and enable the bipolar configuration with high voltage, which has the potential to increase energy density. However, the conventional layer-by-layer (LbL) stacking process using individual electrolyte and electrode layers suffers from poor electrolyte–electrode contacts and challenging process complications for manufacturing multi-layer bipolar SSBs. Herein, we report an electrode-to-electrode (EtE) monolithic integration without a free-standing solid electrolyte layer for high-voltage bipolar SSBs. Positive and negative electrodes seamlessly combined with a thin solid electrolyte are fabricated by the infusion of a plastic-crystal-based polymer electrolyte (PCPE) into porous electrodes with a subsequent UV-induced solidification process. The infused PCPE in the electrodes forms continuous Li⁺ conduction channels as well as intimate solid–solid interfaces. The thin PCPE film formed in situ on the top of the electrodes during the infusion process provides high Li⁺ conductance between the two electrodes. SSBs constructed via direct integration of the PCPE-infused electrodes exhibits superior electrochemical performances than the SSB fabricated by the conventional LbL stacking process. Moreover, a 10 V-class, bipolar SSB comprising five unit cells stacked in series is constructed via the EtE monolithic integration of multiple PCPE-infused bipolar electrodes, and its stable cycle performance is demonstrated.