Electrode Material For Micro-supercapacitors Research Articles

Recent progress of stretchable MXene based micro-supercapacitors

The rapid development of wearable electronics has stimulated the urgent demand for compatible, miniaturized energy storage devices. As one of the most promising candidates, micro-supercapacitors (MSCs) have attracted significant attention, owing to their high power densities, long operation life, and fast charge/discharge rate. In comparison to conventional, rigid MSCs, deformable MSCs are attracting more and more attention for their superior tolerance to various deformations, including stretching, bending, and twisting, guaranteeing smooth operation of the wearable electronics. MXenes, a class of emerging two-dimensional transition metal carbonitrides/nitrides, have metallic conductivity, high specific surface area, good hydrophilicity, and surface chemical tunability, showing great potential as electrode material for MSCs. In this paper, the recent progress, focused on the MXene-based, stretchable MSCs with fiber-shaped, planar configuration, is systematically summarized. Moreover, the key challenges and prospects of MXene-based, stretchable MSCs for practical application are discussed, which are critical for further development of them.

Boron and fluorine Co-doped laser-induced graphene towards high-performance micro-supercapacitors

Laser-induced graphene (LIG) has attracted extensive research as an electrode material for micro-supercapacitors (MSC). However, the low capacitive performance of LIG arising from both limited specific surface area and few active sites remains challenging. Herein, in situ doping of fluorine and boron atoms into laser-induced graphene was innovatively achieved via laser direct writing approach using boron-doped fluorinated polyimide (FB-PI) as the precursor. The porous fluorine and boron co-doped laser-induced graphene (FB-LIG) exhibits more active sites and improved wettability and significantly enhanced capacitive performance due to the synergistic effect of fluorine and boron co-doping. By tuning the weight ratio of boron to fluorine, the MSC utilizing FB-LIG as the electrode and poly(vinyl alcohol) (PVA)/H2SO4 as the gel electrolyte delivers a high areal capacitance of 49.81 mF/cm2 at a current density of 0.09 mA/cm2, 23 times higher that of MSC from commercial polyimide (PI)-based LIG, and 3 times that of MSC from fluorinated PI-based LIG. In addition, MSCs from FB-LIG possess excellent mechanical stability and flexibility, rendering them promising for flexible wearable microelectronics.

Engineered Electrode Structure for High‐Performance 3D‐Printed All‐Solid‐State Flexible Microsupercapacitors

Graphene aggregation is the major issue limiting its electrochemical performance when used as electrode material for microsupercapacitors (MSCs) with the interdigitated architecture. Solving this issue boosts the device's electrochemical performance, especially the areal energy density, facilitating its applications in advanced miniaturized electronic systems. Herein, a facile method to prepare the graphene−carbon black composite ink for the direct 3D printing of electrodes of MSCs is developed. Carbon black present in the composite ink tailors the graphene sheets space in the electrode structure during the 3D printing process, relieving the graphene aggregation issue. The MSCs show great improved electrochemical performance with a high areal energy density (2.49 μWh cm−2), high power density (0.25 mW cm−2), promising cycling stability, and good mechanical flexibility. The method developed herein paves a way to prepare high‐performance, all‐solid‐state flexible MSCs in a scalable process.

Recent Progress in Graphene‐Based Microsupercapacitors

The fast growing field of microsized electronic devices has urgent demand for next‐generation microscale, flexible, and lightweight energy conversion and storage devices. Among the various microdevices, microsupercapacitors (MSCs) are a promising energy storage device due to their fast rechargeability, better rate capability, long cycle life, and ultrahigh power density. The 2D graphene possesses a large surface area with flexibility, better conductivity, transparency, and high quantum capacitance that lead to an ideal energy storage material for the MSCs. Therefore, this review aims to summarize recent advances in graphene‐based MSCs. A particular emphasis is put on the various fabrication technologies for MSCs such as printing, laser, wet‐spin, and photolithography technique that are discussed elaborately. Moreover, an overview of the state‐of‐the‐art on graphene‐based electrode materials and its different composite with transition metal oxides, transition metal hydroxides, conducting polymers, transition metal chalcogenides, and MXene‐based electrode materials for MSCs are discussed and their electrochemical performances are summarized. Furthermore, this review concludes with perspectives and outlooks.

Bottom-Up, On-Surface-Synthesized Armchair Graphene Nanoribbons for Ultra-High-Power Micro-Supercapacitors.

Bottom-up-synthesized graphene nanoribbons (GNRs) with excellent electronic properties are promising materials for energy storage systems. Herein, we report bottom-up-synthesized GNR films employed as electrode materials for micro-supercapacitors (MSCs). The micro-device delivers an excellent volumetric capacitance and an ultra-high power density. The electrochemical performance of MSCs could be correlated with the charge carrier mobility within the differently employed GNRs, as determined by pump–probe terahertz spectroscopy studies.

Silicon carbide nanowires as highly robust electrodes for micro-supercapacitors

The effectiveness of silicon carbide (SiC) nanowires (NW) as electrode material for micro-supercapacitors has been investigated. SiC NWs are grown on a SiC thin film coated with a thin Ni catalyst layer via a chemical vapor deposition route at 950 °C. A specific capacitance in the range of ∼240 μF cm−2 is demonstrated, which is comparable to the values recently reported for planar micro-supercapacitor electrodes. Charge–discharge studies demonstrate the SiC nanowires exhibit exceptional stability, with 95% capacitance retention after 2 × 105 charge/discharge cycles in an environmentally benign, aqueous electrolyte.