Prof. Gao Yihua’s Team Advances in the Field of Supercapacitor and Piezoresistive Sensor

July 10, 2018

In recent months, multiple research achievements made by Professor Gao Yihua’s team from School of Physics, were published on Nano Energy and ACS Nano.

On April 12, Prof. Gao’s team published a research article on ACS Nano (Impact factor: 13.70) — a prestigious journal of the American Chemical Society.

The wide application of portable and wearable electronic devices highlights the value of microsupercapacitors (MSC) as basic units of energy supply. As supercapacitor-photodetector is equipped with multi-functional integrated system, it possesses great advantages in chemical and biological perception, pharmacotherapy and environmental monitoring. However, currently integrated systems of supercapacitor-photodetectors all adopt an external connection, which leads to greater energy and space waste. Therefore research on self-healable supercapacitors, increasing high-performance downloads and internal self-connection is of particular significance when it comes to practical application. Nonetheless, MSCs are prone to mechanical deformation in practical use, resulting in damaged performance. Meanwhile, supercapacitors’ loading of active materials is generally very low and their performance significantly weakens as the loading capacity increases.

Based on this, Prof. Gao’s team fabricated MXene-rGO composite aerogel with excellent mechanical properties, which combines rGO's large specific surface area and MXene's high conductivity, thus effectively preventing self-stacking of lamellar structure. The MSCs, based on 3D MXene-rGO aerogel, display a large specific area capacitance of 34.6 mF cm-2 and an outstanding cycling performance with a capacitance retention up to 91% over 15,000 cycles. By further wrapping itself with a self-healing carboxylated polyurethane (PU) shell, the 3D MSC also presents an excellent self-healing ability, keeping 81.7% specific capacitance after the 5th healing.

On April 12, ACS Nano published another research of the team, entitled 3D Synergistical MXene/Reduced Graphene Oxide Aerogel for a Piezoresistive Sensor. The team fabricated a high-sensitivity sensor based on the MX/rGO hybrid 3D aerogel. They dispersed small-sized MXene nanosheets into the colloidal solution of grapheme oxide nanosheets and then synthesized MX/rGO hybrid 3D aerogel via free-drying and low temperature annealing, which, if applied to sensors’ active components, can greatly improve their mechanical strength, with sensitivity (22.56 kPa–1), stability (10000 cycles), response time (200 ms) and detection sensitivity (below 10Pa), etc. better than many carbon materials and high-molecular polymers of the same kind.

On March 7, Nano Energy (impact factor: 13.12) published online 3D hybrid porous MXene-sponge network and its application in piezoresistive sensor, another paper of the team. The team synthesized MXene nanosheets with 2D lamellar structure to highly stretchable skeletons of sponge by one-step dipping-drying method and thus fabricated flexible MXene-sponge hybrid pressure sensitive materials with high sensitivity. Then a high-performance piezoresistive sensor was fabricated by further introducing a single-layer Polyvinyl Alcohol (PVA) nanowires network made by electrostatic spinning. The network can effectively insulate conductive paths between active materials, as a result of which the number of the sensors’ inner electricity transmisision paths increase rapidly as they senses pressure. The sensor presents high sensitivity of 442kPa1, a low detection limit of 9Pa and an excellent durability over 10,000 cycles. Compared with traditional piezoresistive sensors, this sensor is simple in process and excellent in performance, hence offering a new way of manufacturing low-cost high-performance piezoresistive sensors on a large scale.

It’s reported that the team has published a few high-level research papers including two on ACS Nano, one on Small, one on J.Mater.Chem.C and one on J.Mater.Chem.A. These research programs have been funded by National Natural Science Foundation of China and Hubei Natural Science Foundation.

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