An All‐Solid‐State Fiber‐Shaped Aluminum–Air Battery with Flexibility, Stretchability, and High Electrochemical Performance

Abstract

Owing to the high theoretical energy density of metal-air batteries, the aluminum-air battery has been proposed as a promising long-term power supply for electronics. However, the available energy density from the aluminum-air battery is far from that anticipated and is limited by current electrode materials. Herein we described the creation of a new family of all-solid-state fiber-shaped aluminum-air batteries with a specific capacity of 935 mAh g À1 and an energy density of 1168 Wh kg À1 . The synthesis of an electrode composed of cross-stacked aligned carbon-nanotube/silver-nanoparticle sheets contributes to the remarkable electrochemical performance. The fiber shape also provides the aluminum-air batteries with unique advantages; for example, they are flexible and stretchable and can be woven into a variety of textiles for large-scale applications.[ + ] These authors contributed equally to this work.Supporting information for this article can be found under: http://dx.

Super‐Stretchable Zinc–Air Batteries Based on an Alkaline‐Tolerant Dual‐Network Hydrogel Electrolyte

“…[11,12] On the other hand, most super-stretchable hydrogels that are considered as an essential component of a stretchable energy storage device will lose their stretchability under such strong alkaline environment. [18][19][20][21] Although other hydrogels, such as polyacrylic acid (PAA), polyacrylamide (PAM), show strong water-retention capability and high stretchability, [22,23] unfortunately, they will lose their mechanical robustness, especially the stretchability, when they are incorporated with strong alkaline electrolyte. [2,[13][14][15][16][17] However, the PVA-based electrolyte possesses very poor stretchability (even worse when alkaline electrolyte infiltrated), and meanwhile it shows limited ion-transport capability, resulting in poorly electrochemical performance and mechanical flexibility.…”

Wearable Thermocells Based on Gel Electrolytes for the Utilization of Body Heat

“…[13,14] Hence, it is of practical meaning to convert body heat energy, a type of low-grade heat, into electricity for directly powering wearable electronics. [29] Inspired by the successful application of gel electrolytes in solid-state electrochemical energy storage systems and stretchable ionic conductors, [30][31][32][33] we surmised that solid-state or quasi-solidstate gel electrolytes may enable the large-scale integration of thermocells.Herein, we report an integrated wearable thermocell based on gel electrolytes for low-grade thermal energy conversion. Traditional thermoelectric generators utilizing the Seebeck effect are mainly based on solidstate semiconductors or conducting polymers, [18,19] with output voltages limited by the relatively low Seebeck coefficient (several hundreds mV K À1 ).…”

“…[20] Alternatively, a large thermovoltage can be derived from thermogalvanic effects, resulting from temperature-dependent entropy changes during electron transfer between redox couples and electrodes. [29] Inspired by the successful application of gel electrolytes in solid-state electrochemical energy storage systems and stretchable ionic conductors, [30][31][32][33] we surmised that solid-state or quasi-solidstate gel electrolytes may enable the large-scale integration of thermocells. However, because of the aqueous electrolytes used in thermocells, large-scale integration and packaging of the units would be more difficult in applications, especially for wearable devices.…”

Toward Soft Skin‐Like Wearable and Implantable Energy Devices

“…In addition, a reversible capacity density of ≈2.5 mA h cm −2 is achieved after multiple iterations of 100% stretching. [94] Moreover, stretchable metal-air batteries, such as zinc-air batteries [95] and aluminium-air batteries, [96] have also been reported recently. In principle, a metal-air battery possesses a theoretical energy density much higher than that of the currently-dominant lithium-ion battery, which is promising for thin, skin-like energy devices for wearable and implantable electronics.…”