Abstract: Inorganic perovskite solar cells (IPSCs) have attracted considerable attention due to their excellent light and thermal stability. However, IPSCs usually face extremely large open circuit voltage (V_OC) deficits due to severe non-radiative recombination at the interface. To solve this issue, this research proposes to use inorganic material cobalt iodide (CoI₂) to inhibit interface non-radiative recombination, enhance the photovoltaic performance of IPSCs without introducing organic materials, achieve effective management of interface defects, reduce non-radiative recombination. IPSCs prepared in air environment based on CoI₂ interface treatment achieved a photoelectric conversion efficiency of 19.50%, and V_OC loss was only 447 mV with excellent stability, providing a new strategy for effectively reducing V_OC deficits of IPSCs.