A Multidimensional Topotactic Host Composite Anode Toward Transparent Flexible Potassium-Ion Microcapacitors

Abstract

Transparent flexible supercapacitors (TFSCs) are a tantalizing power supplier for future transparent flexible electronics. However, their energy density is far behind a practical level while maintaining high transparency. We report here a transparent flexible potassium-ion microcapacitor, and its high energy density (15.5 μWh cm −2 ) roots in the battery-supercapacitor hybrid storage mechanism and much enlarged working voltage (3 V), outperforming the state-of-the-art TFSC, which is generally based on an aqueous electrolyte and an asymmetric pseudocapacitive mechanism. From an electrode material perspective, a multidimensional topotactic host composite anode is designed in which the component not only performs energy storage by synchronous and reversible uptake of potassium ions and electrons into its host structure, but also mutually compensates individual weakness in functional and structural aspects, efficiently constructing a three-dimensional potassium-ion diffusion and electron transport system. This conceptual exhibition provides design principles at material and device levels for high-performance TFSCs.

Fast Kinetic Carbon Anode Inherited and Developed from Architectural Designed Porous Aromatic Framework for Flexible Lithium Ion Micro Capacitors

“…Preparation of Quasi-Gel-Polymer-Electrolyte: The quasi-gel-polymerelectrolyte could be prepared based on previous reports. [67][68][69] Typically, 0.8 g polyvinylidene fluoride hexafluoropropylene (PVDF-HFP) and 0.04 g polyethylene oxide (PEO) were mixed with acetone (10 mL) and ethanol (2 mL). The mixture was stirred at 60 °C for 6 h until it becomes a transparent gel.…”

Advanced Electrode Materials for Potassium‐Ion Hybrid Capacitors

“…[42,[112][113][114] Bai et al reported an in situ hydrothermal method to synthesize materials (TF-PIMCs) with a stable tunnel structure by combing 1D K 2 Ti 6 O 13 nanobelts with quasi-2D graphite nanosheets (Figure 14a). [111] A successful proposal has been made for a multidimensional topotactic host composite anode. This anode utilizes a topotactic potassium-ion intercalation mechanism, resulting in superior rate performances and cycling stability for both gravimetric and volumetric measurements (Figure 14b).…”

“…Figure 14. a) Fabrication procedures, electrodes, and energy storage mechanism of TF-PIMCs. b) Gravimetric rate performances of the KTO/graphite anode.Reproduced with permission from Ref [111]…”