Compressible Zn–Air Batteries Based on Metal–Organic Frameworks Nanoflake‐Assembled Carbon Frameworks for Portable Motion and Temperature Monitors

Abstract

High‐performance and integrated power sources are critical to the practical application of wearable sensors, enabling monitoring of physical signs in real time. However, realizing both good battery performance and portability for batteries is still a challenge to such integration application. Herein, a novel cathode material of flexible zinc–air battery is developed, i.e., NiFe‐based metal–organic frameworks nanoflakes assembled on the carbon frameworks with nitrogen‐heteroatom dopant (NiFe NF/NCFs). Benefiting from the unique interfacial interaction of 2D materials, as well as the rational integration of multifunctional electrocatalytic components in a flexible and compressible skeleton, the prepared NiFe NF/NCFs exhibits excellent activities for oxygen evolution/reduction reactions. Moreover, it achieves high peak power density (107.2 mW cm−2) and specific capacity (814.2 mAh g−1) when served as the cathode of zinc–air batteries. Importantly, serving as both battery cathode and sensing unit, a strain sensor–battery integration device is also demonstrated based on the NiFe NF/NCFs, which displays a favorable strain sensitivity toward detecting human motions. This work provides a new pathway to the development of energy storage device for flexible electronics.

Tunable Heterogeneous FeCo Alloy-Mo0.82N Bifunctional Electrocatalysts for Temperature-Adapted Zn–Air Batteries

“…The anode of Pt/C + RuO 2 served as the control sample, which was prepared by a similar process except that 5 mg of Pt/C and 5 mg of RuO 2 were used during the preparation of the ink. The PAM-CNF gel was obtained by the following steps: 0.5 g of acrylamide was first dissolved in 5.0 g of aqueous dispersion cellulose nanofibers (1.69 wt %), and then 0.01 g of potassium persulfate and 1 mg of N , N ′-methylene-bis-acrylamide were added under vigorous stirring. Subsequently, the above solution was poured into a mold (0.5 mm thick) and polymerized under 60 °C for 2.5 h to prepare the gel.…”

Polymer Electrolytes for Al-Air Batteries: Current State and Future Perspectives

“…Furthermore, when aqueous solutions in the preparation of polymer electrolytes are used, based on the physical characteristics of the obtained electrolyte (mainly deformability and elasticity), safe electrochemical devices can be built to be used in smart devices, 27 such as wearable medical equipment. 28 However, a solid or gel polymer electrolyte is a demanding material to make, because it should have, in addition to the fundamental characteristics of avoiding internal short circuits between the anode and the cathode, good ionic conductivity, having sufficient water retention, and, at the same time, maintaining high mechanical strength and chemical stability to withstand strongly acidic or alkaline environments. Getting a material with all these characteristics at once is challenging.…”

“…Polymer electrolytes represent an advance, with respect to the absence of leaks, and also avoids the use of separators, greatly simplifying the battery design. Furthermore, when aqueous solutions in the preparation of polymer electrolytes are used, based on the physical characteristics of the obtained electrolyte (mainly deformability and elasticity), safe electrochemical devices can be built to be used in smart devices, such as wearable medical equipment …”

Aqueous Batteries for Human Body Electronic Devices

“…As the core component of electronic devices, the energy hub plays an important role in maintaining the normal operation of electronic devices. The electronics become more deeply applied and functionally complex in the human body from outside to inside, and more demanding requirements are placed on the energy hub: absolute safety and high energy density. , As an electrochemical energy storage system, batteries that can efficiently convert chemical energy into electrical energy have unique advantages in this regard. , Unlike Li-ion batteries with organic electrolytes which are prone to leakage and are toxic and flammable, aqueous batteries are becoming the energy hub of choice for these electronic devices, relying on the stability and biocompatibility of an aqueous electrolyte. − In particular, the rapid development of aqueous batteries in recent years, led by aqueous Zn batteries, has culminated in their application in wearable and implantable electronic devices, benefiting from the low electrode potential of −0.763 V vs standard hydrogen electrode (SHE) and a high theoretical capacity of 820 mAh g –1 as well as the good biocompatibility of Zn metal. − …”