To investigate the degradation mechanism of supercapacitors from world-famous commercial manufacture Nesscap at different failure-mode, post-mortem pore structure and chemical ageing analyses were applied for the positive and negative electrodes components, followed by the ageing behavior characterization during galvanostatic charge/discharge (GCD) cycling at room temperature for 60,000 cycles. From the test results, it can be observed that the supercapacitors were damaged to some extent at higher currents (>4 A), while the devices were destroyed at excess voltage (>3.2 V). The main reason in chemical composition for the difference was that a large amount of binder disappeared from the aged electrodes at higher voltage and there was a passivation film formed on the surface of the collector, while slight variation existed in the electrode materials of the aged supercapacitors at higher current. The components deterioration further damaged the unity of the electrodes and caused the increase of the resistance and the decrease of the capacity. (C) 2018 Elsevier Ltd. All rights reserved.