Polyoxometalate‐Based Metal‐Organic Framework/Polypyrrole Composites toward Enhanced Supercapacitor Performance

Abstract

Supercapacitors are energy storage equipment that have attracted particular attention owing to its wide operating temperature range, high-power density, and small size, whereas the limited energy density has always been a main obstacle in many applications. Composite materials have a forward-looking application value in the manufacture of innovative supercapacitors due to the synergistic effect between various components. We propose a plain oxidative polymerization method to prepare the polyoxometalate-based metal-organic framework/polypyrrole composites (PW 12 @MIL-101/PPy-n, n represents the volumes of pyrrole) toward supercapacitor electrodes for the first time. PW 12 @MIL-101 possesses rich and fully accessible active sites as well as regular porosity provided by PW 12 and MIL-101(Fe), respectively. PPy can effectively meliorate the conductivity of PW 12 @MIL-101 by accelerating the Faradaic process at the surface, and then facilitate electron/ion transfer between PW 12 @MIL-101 nanocrystallines. As a result, PW 12 @MIL-101/PPy-0.15 composite has a noticeably higher specific capacitance (1217 mF • cm À 2 ), which is better than PW 12 @MIL-101 (158 mF • cm À 2 ) and MIL-101 (117 mF • cm À 2 ). Meanwhile, the relevant symmetric supercapacitor assembled with PW 12 @MIL-101/PPy-0.15 displays a sizable energy density of 20.7 Wh/kg at a power density of 277.6 W/kg. About 83.7 % of the pristine capacitance is still reserved after 2000 consecutive charges and discharges.

Investigation of Supercapacitor Electrodes Based on MIL-101(Fe) Metal-Organic Framework: Evaluating Electrochemical Performance through Hydrothermal and Microwave-Assisted Synthesis

“…Figure 7f provides the Ragone plot, illustrating the calculated relationship between the energy and power densities of the fabricated SSCD by employing Equations ( 2) and (3). Remarkably, the MF(ht) SSC device attains an impressive peak energy density of 74.7 Wh/kg at a power density of 3780 W/kg, surpassing previously reported values for both energy and power densities [6,[48][49][50]. For an extensive comparative analysis of these parameters with those of other symmetric supercapacitor devices, please refer to Table 2.…”

Huge Electron Sponge of Polyoxometalate toward Advanced Lithium-Ion Storage

“…A Keggin-type polyoxometalate (PMo 12 ) was first reported to be used as the anode material of LIBs in 2012, and it was found that each PMo 12 molecule reversibly transfers 24 electrons during the lithiation and delithiation processes . From then on, some smaller POMs, including PMo 12 , − PMo 10 V 2 , − PW 12 , , SiW 12 , Co 8 W 12 , and so on, which are combined with functional support materials, such as MXene, − organic linkers, , MOFs, − CNTs, , and GO, , were mainly reported for energy storage.…”

Structural and dielectrical behavior of polypyrrole/huntite composites

“…Many composite and nanocomposite materials are currently being developed using PPy. For example, Li et al [ 4 ] prepared polyoxometalate-based metal-organic framework/PPy composites by oxidative polymerization method to be used as electrodes in supercapacitors. It has been reported that the obtained composite electrodes contain abundant active regions with suitable pores and have good conductivity.…”