Design of Architectures and Materials in In‐Plane Micro‐supercapacitors: Current Status and Future Challenges

Abstract

The rapid development of integrated electronics and the boom in miniaturized and portable devices have increased the demand for miniaturized and on-chip energy storage units. Currently thin-film batteries or microsized batteries are commercially available for miniaturized devices. However, they still suffer from several limitations, such as short lifetime, low power density, and complex architecture, which limit their integration. Supercapacitors can surmount all these limitations. Particularly for micro-supercapacitors with planar architectures, due to their unique design of the in-plane electrode finger arrays, they possess the merits of easy fabrication and integration into on-chip miniaturized electronics. Here, the focus is on the different strategies to design electrode finger arrays and the material engineering of in-plane micro-supercapacitors. It is expected that the advances in micro-supercapacitors with in-plane architectures will offer new opportunities for the miniaturization and integration of energy-storage units for portable devices and on-chip electronics.

Kirigami Patterning of MXene/Bacterial Cellulose Composite Paper for All‐Solid‐State Stretchable Micro‐Supercapacitor Arrays

“…[40][41][42] Employing a new electrode material with a high specific capacitance to design and fabricate the MSC islands is the most direct and effective method to improve the poor areal capacitance of MSCAs based on conventional carbon materials. [40][41][42] Employing a new electrode material with a high specific capacitance to design and fabricate the MSC islands is the most direct and effective method to improve the poor areal capacitance of MSCAs based on conventional carbon materials.…”

All-solid-state high-energy planar hybrid micro-supercapacitors based on 2D VN nanosheets and Co(OH)2 nanoflowers

“…1 In this context, planar micro-supercapacitors (MSs) possess the intriguing merits of thinness, high power density, long-term cyclability, and fast charge-discharge capability, which are recognized as one of the most important microscale power sources for integrated electronics. [2][3][4][5][6] On the other hand, hybrid supercapacitors (HSCs) deliver higher energy density than symmetric supercapacitors and larger power density than lithium ion batteries, originating from the extended voltage working windows (e.g., 1.5~2 V in aqueous electrolyte) of advanced asymmetric device geometry, efficiently combining the advantages of supercapacitive electrode with battery-like electrode into single device system. 7,8 Up to now, enormous advances have been made on the development of high-peformance electrodes in sandwich-like HSCs, such as positive electrodes of capacitive counterparts (e.g., active carbon (AC), 9 graphite, 10 and graphene 11 ), redox-active metal oxides/ hydroxides (e.g., MnO 2 16 ), electrically conducting polymers 17 and their hybrids, 18 and negative electrode materials covering all types of nanocarbons (AC, 19 porous carbon, 20 CNT, 21 , and metal nitrides (e.g., titanium nitride, 25 vanadium nitride (VN) 26 ).…”

All‐Solid‐State Planar Sodium‐Ion Microcapacitors with Multidirectional Fast Ion Diffusion Pathways

“…[18][19][20] In contrast, MSCs can fully reversibly adsorb/desorb electrolyte ions or perform fast faradaic reaction at the interface of electrode and electrolyte, affording high power density of up to 1000 W cm −3 , fast charge and discharge rate, and longevity, [21][22][23] while they suffer from low energy density, usually less than 5 mWh cm −3 . [1][2][3][4][5][6][7][8] In principle, Herein, the first prototype planar sodium-ion microcapacitors (NIMCs) are constructed based on the interdigital microelectrodes of urchin-like sodium titanate as faradaic anode and nanoporous activated graphene as non-faradaic cathode along with high-voltage ionogel electrolyte on a single flexible substrate.…”