The field of all-polymer solar cells (all-PSCs) has experienced rapid development during the past few years,mainly driven by the development of efficient polymer acceptors.However,the power conversion efficiencies (PCEs) of the all-PSCs are still limited by insufficient light absorption of the donor/acceptor blend and large energy loss in devices.We herein designed a polymer acceptor PYT1 constructed n-type molecular acceptor Y5-C20 as the key building block and blended it with a polymer donor PM6 to obtain an all-polymer photoactive layer.The optimized PM6:PYT1 all-PSCs achieved a record higher PCE of 13.43％ with a very low energy loss of 0.47 eV and a photoresponse of up to 900 nm compared with the Y5-C20 based device with a best PCE of 9.42％.Furthermore,the PCEs of the PM6:PYT1 all-PSCs are relatively insensitive to the 1-chloronaphthalene (CN) additive contents and active layer thickness.Our results also highlight the effect of CN additive on PM6:PYT1 morphology,i.e.,charge generation,and transport find an optimized balance,and radiative and non-radiative loss is simultaneously reduced in the blend.This work promotes the development of high-performance polymer acceptors and heralds a brighter future of all-PSCs for commercial applications.