A nickel-based compound layer was prepared on a nickel plate by anodization in a 75 wt% H_3PO_4 solution containing NH_4F. This layer was then treated by galvanostatic charge/discharge(GCD) until a black outer layer was detached, leaving behind a film on the nickel plate as a binder-free electrode material for supercapacitors. The microstructural characterization shows that the film consists of Ni(OH)_2and NiO, and no fluoride is found in the as-obtained film. Electrochemical tests demonstrate that this fluoride-free film electrode exhibits a high capacitance of 954 F g~(-1)at 7.5 Ag~(-1), excellent rate capability(a 19.5 % capacitance reduction with the current density increasing to 120 Ag~(-1)) and cycling stability.Within 3500 cycles, the specific capacitance does not decrease, but rather increases from 840 Fg~(-1)to approximately 1092 Fg~(-1)in the first 100 cycles at 60 Ag~(-1), and remains stable until the aforementioned layer is detached. A nickel-based compound was was prepared on a nickel plate by anodization in a 75 wt% H_3PO_4 solution containing NH_4F. This layer was then treated by galvanostatic charge / discharge (GCD) until a black outer layer was detached, leaving behind a film on The microstructure of characterization shows that the film consists of Ni (OH) _2 and NiO, and no fluoride is found in the as-obtained film. Electrochemical tests demonstrate that this fluoride-free film electrode exhibits a high capacitance of 954 F g -1 at 7.5 Ag -1, excellent rate capability (a 19.5% capacitance reduction with the current density increasing to 120 Ag -1) and cycling stability. Within 3500 cycles, the specific capacitance does not decrease, but rather increases from 840 Fg -1 to approximately 1092 Fg -1 in the first 100 cycles at 60 Ag -1, and remains stable until the The layer is is detached.