Non-volatile resistive random-access memory (ReRAM) is a promising candidate for next-generation information storage, such as radiation-resistant memory modules and multifunctional memristor for sensing, data storage, and computing. However, ReRAM faces critical challenges in simultaneously achieving high on/off ratios and low reset current density due to conflicting material requirements that demand both high electrical conductivity and low thermal conductivity. Herein, we propose a novel nanoparticles (NPs)-array-air spacer (NAAS) passivated strategy to resolve the inherent electrical-thermal conductivity trade-off in ReRAM design. Specifically, we demonstrated an Al/polymethyl methacrylate (PMMA)/NAAS/indium tin oxide (ITO) memristor featuring the highest on/off ratio (10⁷) and the lowest reset current density (10⁻⁹ A/cm² at 0.02 V read) reported to date. The Au NAAS, formed by monodisperse Au NPs self-assembled on ITO and interstitial air gaps, served as a passivated layer between ITO and suspended PMMA film. Both experimental characterization and electrical/thermal simulations confirm that such unique architecture strategically decouples the conflicting requirements by reducing overall thermal conductivity while enhancing local electrical conductivity, yielding simultaneously a record-high on/off ratio and ultralow reset current density. This spatial passivation strategy transcends conventional single-material approaches, providing a universal design paradigm for reconciling conflicting material requirements in nanoscale resistive switching devices.