Dry-processed electrodes (DPEs) offer a promising route to reduce manufacturing cost and environmental impact on lithium-ion batteries. However, weak interfacial adhesion between polytetrafluoroethylene (PTFE)-based DPEs and metallic current collectors leads to unstable electronic contact and performance degradation. Although primer layers are widely used to address this issue, how primer layer design governs the interfacial properties, and ultimately electrochemical performance, remains poorly understood. Herein, we systematically investigate carbon-based primer layers composed of carbon black (Super P) and carbon nanotubes (CNTs) by combining experimental characterization with digital twin-based modeling to determine how interfacial contact and electronic properties affect DPE performance. A hybrid primer layer with a balanced Super P/CNT ratio of 50:50 achieves robust interfacial integrity and uniform electron transport, resulting in enhanced rate capability and stable cycling. This study provides practical design guidelines for primer layer engineering toward mechanically robust and electrochemically stable DPEs.