Sodium Ion Microscale Electrochemical Energy Storage Device: Present Status and Future Perspective

Abstract

With the onset of "intelligent" era marked by flexible and wearable microelectronics, the Internet of Things (IoT), implantable medical devices, smart sensors, and wireless charging, [1-4] conventional electrochemical energy storage devices (EESDs) being bulky and rigid cannot meet the demand of rising microelectronics due to poor integrability. [5-7] In addition, conventional EESDs also have severe problems stemming from intrinsic limitation on architecture, for instance, thick commercial separator (glass fiber) limiting the ion diffusion kinetics, and the safety issue of commercial batteries pertaining to the alkali metals (e.g., Li, Na). [8,9] Naturally, their electrochemical performance is subpar and cannot keep up with the development of shapeless and flexible integrated circuits. [10-13] These issues have intensified the pursuit of flexible, versatile, compatible, and on-chip microscale EESDs (MEESDs) as promising power source, which could be integrated with microrobots, wearable devices, or microelectronics with low power consumption (milliwatts to nanowatts). [14-17] Microsupercapacitors (MSCs) with high power density, fast chargedischarge rate and ultra-long life have exhibited easy integration, and good mechanical flexibility, [18,19] which store charge by fast ion adsorption/desorption or highly reversible redox reactions at the interface between the electrode and electrolyte. [20,21] MSCs can power various electronics from watts to microwatts power (Figure 1), but the energy density of MSCs is insufficient to support the high-energy consumption electronics, such as longrange communication, and cannot provide power supply for a long time (hours). [22,23] By contrast, microbatteries (MBs) with high energy density could be hopeful to satisfy the energy requirements of some mobile devices for long-term consumption from nanowatts to milliwatts, such as 32 KHz quartz oscillator in nanowatts, electronic watch in microwatts, and miniature

Aqueous MXene/PH1000 Hybrid Inks for Inkjet‐Printing Micro‐Supercapacitors with Unprecedented Volumetric Capacitance and Modular Self‐Powered Microelectronics

“…[1][2][3][4][5][6][7] Integration of MEESDs with microelectronics can solve an array of problems associated with traditional MEESDs by allowing the conversion of intermittent renewable energy sources (e.g., solar, water, thermal, and mechanical energy) into a usable form through portable systems, hence saving additional power and cost. [8][9][10][11][12][13] The examples of a self-charging electrochromic microsupercapacitor (MSC) integrated with the hybrid tribo/piezoelectric nanogenerators powering a light emitting diode, [14] and a stretchable integrated system composed of a MSC, solar cells, and a strain sensor monitoring arterial pulse [15] show glimpses of a future where energy is harvested and used "on-the-go" without time lag. However, the current microsystems mostly Despite intense development of inkjet printing for scalable and customizable fabrication of power sources, one major shortcoming is the lack of eco-friendly aqueous inks free of additives (e.g., toxic solvents, surfactants).…”

A Multi‐Scale Structural Engineering Strategy for High‐Performance MXene Hydrogel Supercapacitor Electrode

“…In particular, electrochemical capacitors (ECs, also denoted as supercapacitors) that can store electrical energy harvested from intermittent sources and supply electrical energy rapidly have been extensively explored and achieved rapid development in recent years. [ 1 , 2 , 3 ] However, considering the need to efficiently power ubiquitous portable electronics or even larger equipment in our day‐to‐day lives, it is necessary yet challenging to improve their energy density. Viewing from the charge storage mechanism and key components of ECs, this improvement requires not only excellent charge‐storage capability of the electrode materials, but also impactful strategies to optimize the design of the electrode structure.…”

Scalable Assembly of Flexible Ultrathin All‐in‐One Zinc‐Ion Batteries with Highly Stretchable, Editable, and Customizable Functions

“…In this Zn/SWCNTs–RGO composite film, Zn microspheres could be uniformly distributed in the 3D conductive network structure of SWCNTs and RGO sheets (Figure S7, Supporting Information), where RGO sheets can host Zn microspheres and SWCNTs mainly play the role in improving the mechanical strength and conductivity of the composite film. [ 30,31 ] As a result, the conductivity of Zn/SWCNTs–RGO composite film is up to 597 S m −1 . In addition, polymer gel electrolytes usually possess excellent ion‐transport capacity and mechanical property, as a result, they are able to serve as both electrolyte and separator to simplify the configuration of flexible devices.…”