Metal-halide perovskite solar cells (PSCs) have attracted considerable attention during the past decade. However, due to the existence of non-radiative recombination losses, the best power conversion efficiency (PCE) is still lower than the theoretical limit defined by shockley-Queser theory. In this work, we investigate1,2,3-oxathiazin-4(3h)-one,6-methyl-2,2-dioxide (Acesulfame Potassium, abbreviated as AK) as a additional dopant for the 2,2′,7,7′-Tetrakis(N,N-di-p-methoxyphenyl-amine)-9,9′-spirobifluorene (Spiro-OMeTAD) and fabricate PSCs in the air. It is found that 12 mol % fraction of AK relative to lithium bis((trifluoromethyl)sulfonyl)-amide (Li-TFSI) reduced the non-radiative recombination from 86.05 % to 69.23 %, resulting in an average 0.08 V enhancement of Voc. The champion solar cell gives a PCE up to 21.9% and over 84% retention of the initial value during 720 h aging in dry air with 20%~30% humidity.