This study presents a synergistic redox modulation strategy using potassium borohydride (KBH₄) to enhance the performance and stability of nickel oxide (NiOₓ)-based inverted perovskite solar cells (PSCs) and modules. The key challenge addressed is the detrimental redox reactions at the NiOₓ/perovskite interface, primarily due to high-valence Ni⁴⁺ and iodide oxidation in the perovskite film. KBH₄ acts as a dual-function reductant, reducing Ni⁴⁺ on the NiOₓ surface and suppressing iodide oxidation within the perovskite film. This approach significantly reduces non-radiative recombination, increases carrier lifetime, and improves device stability. The NiOₓ surface treatment with KBH₄ reduces the Ni⁴⁺ content and increases Ni³⁺, preventing harmful reactions with perovskite. Additionally, residual KBH₄ on the NiOₓ surface reduces oxidized iodide (I₂) in the perovskite precursor, suppressing I₂ formation during operation. These effects lead to a record power conversion efficiency (PCE) of 24.17% for NiOₓ-based PSCs and 20.2% for NiOₓ-based perovskite solar modules under ambient conditions. The modules retain 94% of their initial efficiency after 2000 hours of continuous illumination at 65°C in ambient air. The study also demonstrates that KBH₄ treatment enhances the quality of the perovskite film, reduces trap densities, and improves optoelectronic properties. The reduction in non-radiative recombination and trap states contributes to the enhanced performance and stability of the devices. The results highlight the effectiveness of KBH₄ in overcoming the challenges associated with NiOₓ-based perovskite solar cells, offering a promising strategy for advancing the commercialization of high-performance perovskite photovoltaics.This study presents a synergistic redox modulation strategy using potassium borohydride (KBH₄) to enhance the performance and stability of nickel oxide (NiOₓ)-based inverted perovskite solar cells (PSCs) and modules. The key challenge addressed is the detrimental redox reactions at the NiOₓ/perovskite interface, primarily due to high-valence Ni⁴⁺ and iodide oxidation in the perovskite film. KBH₄ acts as a dual-function reductant, reducing Ni⁴⁺ on the NiOₓ surface and suppressing iodide oxidation within the perovskite film. This approach significantly reduces non-radiative recombination, increases carrier lifetime, and improves device stability. The NiOₓ surface treatment with KBH₄ reduces the Ni⁴⁺ content and increases Ni³⁺, preventing harmful reactions with perovskite. Additionally, residual KBH₄ on the NiOₓ surface reduces oxidized iodide (I₂) in the perovskite precursor, suppressing I₂ formation during operation. These effects lead to a record power conversion efficiency (PCE) of 24.17% for NiOₓ-based PSCs and 20.2% for NiOₓ-based perovskite solar modules under ambient conditions. The modules retain 94% of their initial efficiency after 2000 hours of continuous illumination at 65°C in ambient air. The study also demonstrates that KBH₄ treatment enhances the quality of the perovskite film, reduces trap densities, and improves optoelectronic properties. The reduction in non-radiative recombination and trap states contributes to the enhanced performance and stability of the devices. The results highlight the effectiveness of KBH₄ in overcoming the challenges associated with NiOₓ-based perovskite solar cells, offering a promising strategy for advancing the commercialization of high-performance perovskite photovoltaics.