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• Low-temperature sintered AgNPs pastes were quickly prepared in batches. • The organic shell can effectively avoid the spontaneous bonding of AgNPs. • Citric acid can remove the native oxide layer and promote sintering activity. • After sintering at 220 °C for 30 min, the thermal conductivity exceeded 200 W/mK. This study developed a low-temperature pressureless sintered Ag nanoparticles (AgNPs) paste with high thermal conductivity (TC), which can be produced on a large scale through rapid pre-treatment. Commercially available unmodified AgNPs were coated with polyvinylpyrrolidone (PVP), and subsequently, citric acid (CA) was used to remove the native oxide layer from the AgNPs surface and improve sintering activity. Compared to the treatment strategy of CA activation followed by PVP coating, applying PVP coating prior to CA activation could prevent their spontaneous bonding that will significantly promote the formation of large grains and strong sintering necks, reducing the interface scattering and leading to an ultra-high TC (≥200 W/mK), thereby meeting the packaging requirements of high-power electronic applications. [ABSTRACT FROM AUTHOR]