Updated Insights into 3D Architecture Electrodes for Micropower Sources

Abstract

Microbatteries (MBs) and microsupercapacitors (MSCs) are primary on‐chip micropower sources that drive autonomous and stand‐alone microelectronic devices for implementation of the Internet of Things (IoT). However, the performance of conventional MBs and MSCs is restricted by their 2D thin‐film electrode design, and these devices struggle to satisfy the increasing IoT energy demands for high energy density, high power density, and long lifespan. The energy densities of MBs and MSCs can be improved significantly through adoption of a 2D thick‐film electrode design; however, their power densities and lifespans deteriorate with increased electrode thickness. In contrast, 3D architecture electrodes offer remarkable opportunities to simultaneously improve MB and MSC energy density, power density, and lifespan. To date, various 3D architecture electrodes have been designed, fabricated, and investigated for MBs and MSCs. This review provides an update on the principal superiorities of 3D architecture electrodes over 2D thick‐film electrodes in the context of improved MB and MSC energy density, power density, and lifespan. In addition, the most recent and representative progress in 3D architecture electrode development for MBs and MSCs is highlighted. Finally, present challenges are discussed and key perspectives for future research in this field are outlined.

Emerging smart design of electrodes for micro‐supercapacitors: A review

“…However, suitable inks of active materials are still limited and the printing resolution is also needed to be further improved. 52 Furthermore, to maintain the complex morphologies of current collectors/scaffolds, conformal deposition techniques of thin film are desired. The ALD technique is a suitable alternative to achieve this goal, which ensures controlling the thickness of active material layer at the atomic level.…”

“…However, suitable inks of active materials are still limited and the printing resolution is also needed to be further improved. 52 Although significant progress have been achieved of MSCs based on LbL-based electrode design strategy, there are still some key aspects, to which need to be paid high attention: (ⅰ) considering the matching degree of the thermal properties of each component materials to avoid the separation of thin films during the manufacturing and charge-discharge processes; (ⅱ) preventing the collapse of bilayer materials caused by volume expansion during the charging-discharging process, thereby resulting in compromise of electrode stability; and (ⅲ) theoretical simulation and analysis to ensure optimized thickness parameters of each thin film to obtain maximum mass loading and good enough conductivity at the expense of minimum device thickness addition. Nevertheless, it has to be pointed out that the LbL-based assemble is not compatible well with the MSCs in stacked topology although the LbL technique is simple and effective to enhance the performance of MSCs.…”

“…For instance, the enlarged diameter of nanopore array unit ensures enough space for more electrochemically active material mass loading and sufficient empty voids. 52 The improvement of electrode material deposition results in enhancement of energy capability. Simultaneously, the empty voids ensure various advantages: (ⅰ) fully electrolyte infiltration for sufficient reactions between electrode materials and electrolyte; (ⅱ) facilitating ion transport for high power capability; and (ⅲ) avoiding the collapse of nanostructured electrode materials caused by volume changes during charge-discharge operation process.…”

Perspective on Micro-Supercapacitors

“…Owing to the unique three-dimensional architectures (3D), 3D materials typically have a large specific surface area (>1,000 m 2 g −1 ), which favors the accessibility of ion-active sites as well as improved ion and electron transport, hence facilitating reaction kinetics ( Zhao et al, 2018a ; Liu et al, 2019b ; Lochmann et al, 2018 ). 3D MSCs have received a lot of attention in the last decade because of the obvious improved electrochemical performance of conventional SCs using 3D architecture electrodes, with the goal of developing micropower sources that meet both the dimensional and energetic requirements for on-chip integration ( Figure 4C ) ( Sha et al, 2021 ). Particularly, significant progress has been made in the design and manufacturing of 3D architectural electrodes for the development of 3D MSCs ( Liu et al, 2018b ; Zhao et al, 2018b ; Zhao and Lei, 2020 ).…”

“… Schematic of 3D MSCs (A) ( Liu et al, 2019a ), Brief development featuring representative 3D architecture electrodes for MSCs (B) ( Lei et al, 2020 ), Fabrication and structure of HAN (C) ( Sha et al, 2021 ). …”