Uniform laser reduction GO (LrGO) matrix for flexible miniature supercapacitors (MSC) applications has been achieved by Lanzhou University

Laser reduced graphene oxide (GO) using direct writing technology has the advantages of being highly flexible, mask free and chemical-free, promising the development of miniaturized energy storage devices. However, laser reduction of GO is usually accompanied by demineralization (a violent deoxidation reaction), resulting in the reduced graphene oxide (rGO) film becoming brittle and irregular internal structure, which is detrimental to applications. In this paper, Professors Minghao Yu and Pan Xiaojun of Lanzhou University published Realizing Highly Ordered Laser-Reduced Graphene for High-Performance Flexible in the journal Small Microsupercapacitor "paper presents a prereduction strategy to avoid this detachaption and achieve a uniform laser reduction GO (LrGO) matrix for flexible miniature supercapacitor (MSC) applications. The ascorbic acid pre-reduction process reduces the content of oxygen-containing functional groups on GO in advance, thus reducing gas emission and avoiding unconstrained expansion in the laser reduction process.

In addition, self-assembled skeletons with pre-reduced GO (PGO) nanosheets can be constructed, which is a more suitable laser reduction forehand frame, to build controllable rGO films with uniform porosity. Quasi-solid MSC assembled with laser reduction PGO exhibited a maximum surface capacitance of 88.32 mF cm-2, good cycling performance (capacitance retention of 82% after 2000 cycles), and excellent flexibility (capacitance did not decrease after 5000 cycles). The discovery provides an opportunity to improve the quality of LrGO, which is promising in micro-power devices and other areas.

Text guide

Figure 1, a) shows the flow chart of preparation of MSC LrpGo-based electrode. b) A digital photograph of the LRPGo-based fork finger electrode as manufactured.

Figure 2. a) SEM images of cross section of PGO films partially reduced by laser. b) PGO, c) Boundary between PGO and LrPGO, d-e) Optical image and schematic diagram of LrGO and PGO hydrogel (illustration). f, g) SEM image of cross section of PGO aerogel after freeze-drying.

Figure 3. a) XRD, b) Raman and c) GO, PGO, LrGO and LrPGO C 1s XPS spectra.

Figure 4, a) GCD curve of MSC based on LrGO and LrPGO at 0.5 mA cm−2. b) CV curves of LrpGo-based MSC with different loading qualities at 20 mV s−1 and c) GCD curves at 0.5 mA cm−2. d) Rate performance of LRGo-based and LrrGo-based MSC and e) Nyquist plots in the frequency range 0.01 to 1000 000 Hz. f) CV curves of MSC based on LrGO-30 at different scanning rates from 5 to 200 mV s−1. g) Cyclic performance of MSC based on LrPGO-30. h) regional capacitance and i) LrPGO-30 based MSC and recently reported Lagon diagrams for graphene-based supercapacitors.

Figure 5, a) CV curves of MSC based on Lrgo-30 under different bending states at 100 mV s−1. b) Capacitance retention of MSC based on LrPGO-30 during 5000 bending tests. CV curves of MSC based on LrGO-30 after c) 0, d) 2500 and e) 5000 bends.

summary
In conclusion, a simple pre-reduction GO strategy is proposed to stably construct uniform LrGO membranes. This strategy can not only alleviate deflaring problems caused by gas emission during laser reduction and unconstrained expansion, but also enable rGO films to form relatively uniform and regular microstructure. This work provides new insights into the realization of uniformly porous LrGO substrates, which have potential applications in micro-power devices and other fields.

Source: NetEase