Graphene electrodes for more efficient supercapacitors

Recently, a research group led by Professor Wang Zhenyang from the Institute of Solid State Physics of the Hefei Institutes of Physical Science (HFIPS) reported a new method to prepare high performance supercapacitors with ultra energy storage density. -high.

Of great importance for the practical application of graphene supercapacitors is the construction of 3-D graphene frames with ultra-thick and rich ion transport paths. However, in thicker electrodes, the overall energy storage capacity is limited by insufficient supply of ions to the surface of the electrode material and by poor electron transport properties.

In this work, laser-induced ultra-thick 3-D graphene frameworks up to 320 μm thick were directly cultured on the synthesized polyimide by optimizing the thermal sensitivity of the polyimide to increase the penetration depth. laser. Thus, hierarchical pores were obtained thanks to the rapid release of gaseous products during laser radiation, which facilitated the rapid transport of the ions.

This new structure has balanced the contradiction between the thickness of the electrode and the rapid transport of ions. Pseudocapacitive polypyrrole has further been introduced into graphene frameworks to prepare composite electrodes, which exhibit specific capacities as high as 2412.2 mF cm^-2 at 0.5 mA cm^-2.

As a result, flexible semiconductor micro-supercapacitors have been built with a high energy density of 134.4 μWh cm^-2 at a power density of 325 μW cm^-2.

These results show that these ultra thick graphene electrodes have great potential in the application of supercapacitors which promise high energy storage density.