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Fig. 1. Schematic illustration of the laser-inducing improved growth process of ultra-thick 3D graphene structures with hierarchical pores. Credit: LI Nian
Recently, a research team led by Prof. Wang Zhenyang of the Hefei Institutes of Physical Science (HFIPS) Institute of Solid State Physics reported a new method for preparing high-performance supercapacitors with ultra-high energy storage density.
The construction of 3-D graphene structures with ultra-thick and rich ion transport paths is of great importance for the practical application of graphene supercapacitors. However, in thicker electrodes, the overall energy storage capacity is limited by insufficient delivery of ions to the surface of the electrode material and poor electron transport properties.
In this work, laser-induced ultra-thick 3-D graphene structures, up to 320 μm thick, were grown directly on the synthesized polyimide by optimizing the thermal sensitivity of the polyimide to increase laser penetration depth. Thus, hierarchical pores were obtained due to the rapid release of gaseous products during laser radiation, which facilitated the fast transport of ions.
This new structure has well balanced the contradiction between the thickness of the electrode and the fast transport of ions. Pseudocapacitive polypyrrole has been further introduced into graphene structures to prepare composite electrodes, which show specific capacities up to 2412.2 mF cm-2 at 0.5 mA cm-2.
Fig. 2. Morphology and characterizations of the structure of ultra-thick 3D graphene structures. Credit: LI Nian
As a result, flexible solid-state micro-supercapacitors with a high energy density of 134.4 μWh cm were built.-2 with 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 that promise high energy storage density.
Fig.3. Electrochemical performance of supercapacitors. Credit: LI Nian
The new electrode configuration improves the volumetric performance of the supercapacitors
Xinling Yu et al. Ultra thick 3D graphene structures with hierarchical pores for flexible high performance micro-supercapacitors, Journal of Power Sources (2020). DOI: 10.1016 / j.jpowsour.2020.229075
Provided by the Chinese Academy of Sciences
Quote: Best Performing Graphene Electrodes for Supercapacitors (2020, Nov 11) Retrieved Nov 11, 2020 from https://phys.org/news/2020-11-graphene-electrodes-better-performance-supercapacitors.html
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