Aluminum‐Ion‐Intercalation Supercapacitors with Ultrahigh Areal Capacitance and Highly Enhanced Cycling Stability: Power Supply for Flexible Electrochromic Devices

Abstract

Electrochemical capacitor systems based on Al ions can offer the possibilities of low cost and high safety, together with a three-electron redox-mechanism-based high capacity, and thus are expected to provide a feasible solution to meet ever-increasing energy demands. Here, highly efficient Al-ion intercalation into W O nanowires (W O NWs) with wide lattice spacing and layered single-crystal structure for electrochemical storage is demonstrated. Moreover, a freestanding composite film with a hierarchical porous structure is prepared through vacuum-assisted filtration of a mixed dispersion containing W O NWs and single-walled carbon nanotubes. The as-prepared composite electrode exhibits extremely high areal capacitances of 1.11-2.92 F cm and 459 F cm at 2 mA cm , enhanced electrochemical stability in the Al electrolyte, as well as excellent mechanical properties. An Al-ion-based, flexible, asymmetric electrochemical capacitor is assembled that displays a high volumetric energy density of 19.0 mWh cm at a high power density of 295 mW cm . Finally, the Al-ion-based asymmetric supercapacitor is used as the power source for poly(3-hexylthiophene)-based electrochromic devices, demonstrating their promising capability in flexible electronic devices.

Mesoporous Reduced Graphene Oxide as a High Capacity Cathode for Aluminum Batteries

“…For instance, the ions of aluminum are trivalent and have small ionic radii, allowing for high energy and high power density storage devices. In fact, its theoretical gravimetric and volumetric capacities are 2980 mAh g −1 and 8040 mAh cm −3 , respectively, with the latter representing the largest value among metal‐ion batteries . Unfortunately, the highly charged nature of the Al 3+ ions makes them strikingly hard to intercalate .…”

“…In fact, its theoretical gravimetric and volumetric capacities are 2980 mAh g −1 and 8040 mAh cm −3 , respectively, with the latter representing the largest value among metal‐ion batteries . Unfortunately, the highly charged nature of the Al 3+ ions makes them strikingly hard to intercalate . Moreover, research into Al‐based energy storage systems was historically afflicted by unsuitable electrolytes and the inactive aluminum oxide layer, which degraded battery performance .…”

MoS2/C/C nanofiber with double-layer carbon coating for high cycling stability and rate capability in lithium-ion batteries

“…At the same time, carbon materials can also act as a binder between the S/Li 2 S and the molybdenum to prevent the loss of polysulfide during cycling [1,23,27,28]. Based on these properties, hybrid MoS 2 -carbon systems can lead to better electrode kinetics and more stable cycling performance [29][30][31][32][33].…”

A High Capacity Aluminum‐Ion Battery Based on Imidazole Hydrochloride Electrolyte

“…Therefore, more researchers are investing in the research of electrochemical systems such as Na‐ion batteries, Mg‐ion batteries and Al‐ion batteries with abundant crustal reserves . Al‐ion batteries are expected to be the most potential energy storage system due to characteristics of low‐cost, excellent cycling performance, low flammability and three‐electron‐redox property, and it possesses great theoretical capacity of 2980 mA h g −1 and 8063 mA h cm −3 …”

“…[7] Al-ion batteries are expected to be the most potential energy storage system due to characteristics of low-cost, excellent cycling performance, low flammability and three-electron-redox property, and it possesses great theoretical capacity of 2980 mA h g À 1 and 8063 mA h cm À 3 . [8,9] Dai and co-workers presented a rechargeable Al-ion battery using costly [EMIm]Cl as electrolyte, which achieved a specific capacity of 60 mA h g À 1 . [10] Since then, more researchers have devoted themselves to the field of Al-ion batteries, positive electrode material, [11][12][13][14][15][16] current collector [17][18][19] and electrolyte.…”