Shuge Dai

A Flexible micro-supercapacitor based on a pen ink-carbon fiber thread

A highly flexible solid-state micro-supercapacitor based on a pen ink-carbon-fiber (Ink-CF) thread structure was fabricated with excellent electrochemical performance such as a high capacitance of 4.31 mF cm−2 and an energy density of 3.8 × 10−7 W h cm−2 at a power density of 5.6 × 10−6 W cm−2. This fabricated structure shows excellent characteristics such as lightweight, small volume, flexibility and portability. By integrating it with a triboelectric nanogenarator, the micro-supercapacitors could be charged and power 8 commercial LEDs, demonstrating its feasibility as an efficient storage component for self-powered micro/nanosystems.

Nanorod-aggregated flower-like CuO grown on a carbon fiber fabric for a super high sensitive non-enzymatic glucose sensor

A novel and exceptionally sensitive glucose biosensor based on nanorod-aggregated flower-like CuO grown on a carbon fiber fabric (CFF) is developed for glucose detection, which is prepared by a simple, fast and green hydrothermal method. The electron transfer resistance of the CuO/CFF electrode on the interface between the electrode and the electrolyte is as low as 12.79 Ω as evaluated by electrochemical impedance spectroscopy. A cyclic voltammetry study reveals that the CuO/CFF electrode displays an excellent electrocatalytic activity toward the direct oxidation of glucose. Besides, chronoamperometry demonstrates a high sensitivity of 6476.0 μA mM-1 cm-2 at an applied potential of 0.45 V (vs. Ag/AgCl), with a fast response time and a low detection limit of only 1.3 s and ∼0.27 μM, respectively. In addition, the glucose sensor has high reproducibility with a relative standard deviation (R.S.D.) of 1.53% over eight identically fabricated electrodes and long-term stability with a minimal sensitivity loss of ∼9.9% over a period of one month as well as excellent anti-interference ability. Importantly, the CuO-CFF composite has such good flexible characteristics and can be fabricated into flexible electrodes for application in various complicated circumstances. This work presents a new strategy to achieve highly sensitive glucose sensors with flexibility by growing glucose electroactive nanostructure materials directly on multichannels and highly conductive carbon fiber fabrics.

KCu7S4 nanowires and the Mn/KCu7S4 nanostructure for solid-state supercapacitors

We report a novel pseudocapacitor based on KCu7S4 nanowires. To improve the electrochemical performance of the KCu7S4 capacitor, we changed the structure of the KCu7S4 nanowire electrode by coating Mn particles (Mn/KCu7S4). The preferable capacitance is shown by the Mn/KCu7S4 hybrid capacitor, which displays large specific capacitance (1620 F g−1) at a scan rate of 1 mV s−1, high energy density, good cyclic stability and three supercapacitor units in series light 400 light-emitting diodes (LEDs) for 2 min. The much-increased capacity, rate capability, and cycling stability may be attributed to the Mn/KCu7S4 hybrid structure, which enhances ionic and electronic transport through the electrode system.

Folded Elastic Strip-Based Triboelectric Nanogenerator for Harvesting Human Motion Energy for Multiple Applications

A folded elastic strip-based triboelectric nanogenerator (FS-TENG) made from two folded double-layer elastic strips of Al/PET and PTFE/PET can achieve multiple functions by low frequency mechanical motion. A single FS-TENG with strip width of 3 cm and length of 27 cm can generate a maximum output current, open-circuit voltage, and peak power of 55 μA, 840 V, and 7.33 mW at deformation frequency of 4 Hz with amplitude of 2.5 cm, respectively. This FS-TENG can work as a weight sensor due to its good elasticity. An integrated generator assembled by four FS-TENGs (IFS-TENG) can harvest the energy of human motion like flapping hands and walking steps. In addition, the IFS-TENG combined with electromagnetically induced electricity can achieve a completely self-driven doorbell with flashing lights. Moreover, a box-like generator integrated by four IFS-TENGs inside can work in horizontal or random motion modes and can be improved to harvest energy in all directions. This work promotes the research of completely self-driven systems and energy harvesting of human motion for applications in our daily life.

β-NiMoO4 nanowire arrays grown on carbon cloth for 3D solid asymmetry supercapacitors

Based on β-NiMoO4 nanowire (NW) arrays grown on carbon cloth as the electrode materials, a 3D solid asymmetrical supercapacitor has been fabricated. The produced β-NiMoO4 NW arrays on carbon cloth compared to the power of NiMoO4 nanowires deposited directively on carbon cloth can increase the efficiency of nanomaterials participating in reactions. The cone-shaped NW arrays have a high specific surface area (99 m2 g−1), which can provide more electroactive sites for Li+ and enhance conductivity through providing short transport and diffusion paths for both ions and electrons. And the cylindrical supercapacitor can allow more β-NiMoO4 NW arrays to saturate with electrolyte to enhance the properties of the supercapacitor. Furthermore, the electrode has a highest energy density of 36.86 W h kg−1, a maximum power density of 1100 W kg−1, and a large capacitance of 414.7 F g−1 at a current density of 0.25 A g−1, all of which demonstrate excellent behavior. And the capacitance of the supercapacitor reached 65.96% of the initial capacitance over 6000 cycles. All of these results indicated that the β-NiMoO4 NW arrays grown on carbon cloth could be a promising candidate for high performance supercapacitors.

Enhanced output-power of nanogenerator by modifying PDMS film with lateral ZnO nanotubes and Ag nanowires

In this paper, a nanogenerator based on flexible polydimethylsiloxane (PDMS) film modified with semiconductor zinc-oxide (ZnO) nanotubes and conductive Ag nanowires is designed and fabricated. The modified PDMS film consists of semiconductor ZnO nanotubes distributed on a dielectric PDMS film with conductive Ag nanowires covered on the surface of the ZnO nanotubes and another thin PDMS layer encapsulated on the top, which forms the structure of PDMS/Ag/ZnO/PDMS. The Ag nanowires act as multi-antennal electrodes and play an important role in improvement of output power. The performance of the nanogenerator with different modified PDMS films is investigated under different measurement conditions. The output current density and power density of the generator under periodic stress (20 N) are 10 μA cm and 1.1 mW cm−2, respectively. The instantaneous output current peak can reach as high as 115 μA (23.75 μA cm−2) under a pressure of 90 N which can be used to light up 99 commercial green LEDs connected in series. The output power of this modified PDMS-based nanogenerator is much higher than that of previously reported PDMS-based nanogenerators, demonstrating excellent structural advantages.

C@KCu7S4 microstructure for solid-state supercapacitors

Here we report a high-performance all-solid-state C@KCu7S4 hybrid supercapacitor based on carbon (C) particles coated on a KCu7S4 electrode. The C@KCu7S4 hybrid supercapacitor (2 mg C) shows good electrochemical behavior with a large specific capacitance of 352 F g−1 at a scan rate of 10 mV s−1, the highest energy density of 26.2 W h kg−1 and the highest power density of 994.8 W kg−1, still retaining 86% of the capacitance after 2000 cycles. Moreover, a light-emitting diode (LED) can be lit by three supercapacitors in series for about 3.5 min, indicating the good application prospects of using C@KCu7S4 hybrid supercapacitors for energy storage.