Recently, a team led by Researcher Zhongshuai Wu from the Dalian Institute of Chemical Physics, Chinese Academy of Sciences, in collaboration with Professor Mingbo Wu's team from China University of Petroleum (East China), has made a breakthrough in the research of 3D printed graphene micro-supercapacitors. The collaborative team has developed a high-quality additive-free graphene ink suitable for 3D printing, resulting in micro-supercapacitors with high integration density, high output voltage, and high voltage density. Their findings have been published in "Advanced Materials."
Graphene exhibits excellent mechanical, electrical, and thermal properties, making graphene and its inks promising for a wide range of applications in flexible electronic devices, thermal management devices, bio-material devices, and more. However, existing 3D printing graphene inks involve the use of graphene oxide and various additives, which not only reduce the conductivity, thermal conductivity, and energy density of the devices but also significantly increase the process complexity and costs due to the required freeze-assisted printing, post-reduction treatment, and freeze-drying processes, failing to meet the commercialization demands of 3D printed graphene inks.
In this work, the research team utilized electrochemically exfoliated graphene, glycerol, and water as raw materials to develop a polymer-free, cost-effective, robust, and environmentally friendly 3D printing graphene ink. The microelectrodes or devices printed with this ink do not contain non-active materials like polymers, reducing their adverse effects on energy storage and other potential applications. By using EMIMBF4/PVDF-HFP ionic gel as a quasi-solid-state electrolyte, the team enhanced the electrochemical performance of 3D printed graphene micro-supercapacitors. The specific area capacitance reached 4900mF/cm2, the specific volume capacitance reached 195.6F/cm3, the areal energy density was 2.1mWh/cm2, the volumetric energy density was 23mWh/cm3, and stable cycling performance was achieved at a high voltage of 3.5V and a high temperature of 100°C. Furthermore, to meet the requirements of practical electronic devices for high operating voltages (>100V), the team also achieved a high number of integrated devices in a single 3D printed micro-supercapacitor (188 devices), high integration density (16 devices per unit area), high output voltage (192.5V), and high voltage density (56V/cm2).
This work is expected to provide a scientific basis and application guidance for the commercialization of graphene in the field of 3D printing.
For more information, please refer to the related paper: https://doi.org/10.1002/adma.202313930
