Passivated　contact　crystalline　silicon　(c-Si)　solar　cells　with　nickel　oxide　(NiOx)　as　a　hole　transport　layer　(HTL)　are　a　promising　and　efficient　solar　cell　that　has　received　much　attention.　However,　the　current　low　open　circuit　voltage　(V-oc)　and　low　stability　of　c-Si　solar　cells　with　NiOx　as　the　HTL　are　due　to　the　bad　passivation　and　the　ion　diffusion,　which　has　limited　the　development　of　NiOx-based　c-Si　solar　cells.　Herein,　the　performance　of　doping-free　asymmetric　passivated　contact　c-Si　heterojunction　solar　cells　is　improved　by　using　hydrogen-doped　aluminum　oxide　(H-Al2O3)　as　the　passivation　layer　and　annealing　in　forming　gas　(nitrogen,　hydrogen　mixture　FGA),　as　well　as　by　introducing　an　economically　saving　composite　Ni/Ag　electrode.　Finally,　a　20.29%　power　conversion　efficiency　is　achieved　from　p-Si/H-Al2O3(FGA)/NiOx/Ni/Ag　back-contact　c-Si　solar　cells,　which　is　the　highest　efficiency　reported　so　far　for　c-Si　solar　cells　with　NiOx　as　the　HTLs.　Furthermore,　the　efficiency　of　the　p-Si/H-Al2O3(FGA)/NiOx/Ni/Ag　remains　above　20%　after　30　days　of　storage　in　an　atmospheric　environment,　demonstrating　its　long-term　stability.　This　study　demonstrates　the　potential　for　industrialization　of　NiOx-based　HTL　c-Si　solar　cells　with　high　performance　and　high　stability.