Efficiencies of perovskite solar cells (PSCs) are now hitting such high levels that scalable fabrication at low-cost is becoming pivotal. However, this remains challenging due to expensive metal electrodes and organic hole-transporting materials (OHTMs) typically used in PSCs. By simplifying the device structure, OHTMs-free and noble metal-electrodes-free planar PSCs with the aperture area of 1 cm2 are fabricated with novel NiO@CSs-composite electrodes. The distribution of hole-accepting nickel oxide (NiO) as closely-packed shells on the core carbon spheres (CSs) in the rambutan-like NiO@CSs-composite enhances the photogenerated hole collection efficiency and reduces recombination loss. The small porosity of this composite inhibits the intrusion of the oxygen/moisture through the counter electrode, thus enabling a stable device's efficiency of 11.70% up to 1500 h under 40–60% humidity without encapsulation. The ability to fabricate large-sized planar devices with NiO@CSs-composite electrodes represents a significant step towards the cost-effective and scalable manufacturing with numerous possibilities to choose and optimize the materials, and device's architecture.