The aluminum doped cobalt oxide thin film was prepared through crossed-beam pulsed laser deposition (PLO) of aluminum and cobalt metals in the low-pressure O-2/H-2 atmosphere. The thin film was etched by NaOH to remove aluminum oxide and then cobalt oxide/hydroxide nanowall array film was obtained. The pseudocapacitive performances of the nanowall array film are tested by cyclic voltammetry (CV) and galvanostatic charge-discharge measurements in 1 M KOH aqueous solution. When deposited in the atmosphere of O-2:H-2 = 2:1, the thin film displays a high specific capacitance (690 Fg(-1)) and a superb rate capability (75% capacitance retention from 1 Ag-1 to 120 Ag-1). In addition, excellent cycling stability is achieved for the film electrode and the specific capacitance degradation is only 0.3% after 1000 cycles. (C) 2013 Elsevier Ltd. All rights reserved.