Structural Changes of Activated Carbon Electrodes for EDLCs in the Manufacturing Process

Abstract

Supercapacitors, or electric double-layer capacitors (EDLCs), are the new generation of energy storage devices to store electrical charges and provide high power densities and long cyclic life compared to other storage devices. EDLC mainly consists of activated carbon electrodes and an electrolyte, and the performance of EDLC depends on the activated carbon electrodes. In this work, the structural changes of activated carbon electrodes are analyzed using commercial 2.7 V/9500F EDLCs in its manufacturing process. It is found that there is no significant change in morphology and crystal structure of the activated carbon, but its specific surface area (SSA) reduced greatly. The SSA of activated carbon was decreased by 23% after they were manufactured or converted into electrodes and finally retained only 40% of SSA after the capacitance test. Besides, the SSA of the positive electrodes was found to decrease critically than that of the negative electrodes. The SSA of the external positive electrodes is only 14.3% after floating test at 65 °C.

Keywords

Electrode / EDLCs / Pore structure / Activated carbon / Structural change

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