It is still a challenge to develop aqueous rechargeable Zn-based alkaline batteries with high energy density, power density and excellent stability. Herein, a crystalline/amorphous Co2P2O7 self-supporting on the Ni foam is fabricated as a cathode material of aqueous Zn-based alkaline batteries. The unique crystalline/amorphous structure endows the electrode material with more exposed active sites, higher redox species coverage, larger electrochemical surface area (ECSA), smaller charge-transfer resistance, lower reaction energy barriers and faster electrochemical reaction kinetics process, which clarifies an explicit structure–property relationship simultaneously. As a result, the crystalline/amorphous Co2P2O7 (CP-P-450) electrode assembled as CP-P-450//Zn battery achieves an extraordinary areal capacity of 2.49 mAh cm−2 at 5 mA cm−2, satisfactory rate performance, excellent cyclic durability (96.6 % retention after 4000 cycles) and impressive energy density (4.16 mAh cm−2) and peak power density (115.94 mW cm−2). The quasi-solid CP-P-450//Zn battery can drive a variety of electrical appliances working well even under abuse tests, demonstrating excellent safety and application potential. This study provides an effective strategy towards excellent comprehensive energy storage performance of aqueous Zn-based alkaline batteries through structuring the crystalline/amorphous phase in cathodes.