Sputtering of sub-micrometer aluminum layers as compact, high-performance, light-weight current collector for supercapacitors

• Magnetron sputtering of aluminum generates sub-μm layers on carbon electrodes.
• Strongly enhanced power handling when using sputtered Al as current collector.
• Strongly reduced device mass and volume by use of sub-μm current collector layers.
• Very stable electrochemical performance in organic electrolyte.

Supercapacitors are devices for rapid and efficient electrochemical energy storage and commonly employ carbon coated aluminum foil as the current collector. However, the thickness of the metallic foil and the corresponding added mass lower the specific and volumetric performance on a device level. A promising approach to drastically reduce the mass and volume of the current collector is to directly sputter aluminum on the freestanding electrode instead of adding a metal foil. Our work explores the limitations and performance perspectives of direct sputter coating of aluminum onto carbon film electrodes. The tight and interdigitated interface between the metallic film and the carbon electrode enables high power handling, exceeding the performance and stability of a state-of-the-art carbon coated aluminum foil current collector. In particular, we find an enhancement of 300% in specific power and 186% in specific energy when comparing aluminum sputter coated electrodes with conventional electrodes with Al current collectors.

Figure optionsDownload as PowerPoint slide