Layered potassium vanadate K2V6O16 nanowires: A stable and high capacity cathode material for calcium-ion batteries

A Ca‐Ion Electrochromic Battery via a Water‐in‐Salt Electrolyte

“…In addition, under a high current density of 0.4 mA cm −2 , discharge capacities of 74.7 and 90.2 mAh m −2 are achieved in the 1 and the 5 M electrolytes, respectively (Figure 5d). Notably, the average discharge potential of the InHCF film in the 5 M electrolyte is 0.63 V at 0.05 mA cm −2 , which is much higher than the values obtained in the reported hexacyanoferrates [15,[32][33][34][35]37,38] and other reported cathodes [38,39] (Figure 5e). Furthermore, the Fe 2+ /Fe 3+ redox couple in the InHCF film also gives rise to electrochromism accompanying with the energy storage process.…”

Aqueous Nickel-Ion Batteries with Long Lifetime, High Capacity, and High Rate Capability Based on K2V6O16·1.64H2O Cathodes

“…As shown in Figure a, the obtained results illustrate that most of the characteristic peaks can be well-indexed to monophasic K 2 V 6 O 16 ·1.5H 2 O (PDF#51-0379) and K 2 V 6 O 16 ·2.7H 2 O (PDF#51-0602), indicating that the synthesized particles are mostly composed of K 2 V 6 O 16 · x H 2 O (KVO). The upright inset in Figure a suggests the structure of KVO consisting of layered [V 3 O 8 ] − backbones stabilized by the interstitial hydrated K + ions, which is available for the intercalation/de-intercalation process of guest ions. − TGA was carried out to determine the content of water in the sample. As seen in Figure S1a, the first stage I is the loss of free water, while the second stage II and third stage III correspond to the loss of interlayer water. − Thus, the synthesized particles can be expressed as K 2 V 6 O 16 ·1.64H 2 O (KVO).…”

“…For the high-resolution XPS of K 2p, two characteristic peaks located at 295.3 eV (2p 1/2 ) and 292.6 eV (2p 3/2 ) were detected, testifying the existence of K + in the KVO sample (Figure f). ,, For the high-resolution XPS of V 2p, two characteristic peaks situated at 524.6 eV (2p 1/2 ) and 517.2 eV (2p 3/2 ) were observed, demonstrating the existence of V 5+ in the KVO sample (Figure g). − , For the high-resolution XPS of O 1s, the spectra can be fitted into two peaks located at 530.0 and 531.6 eV, corresponding to the lattice −O and −OH species, respectively. The lattice −OH corresponds to the structural water in the interlayer of KVO (Figure h). − , …”

Simultaneous pre-intercalation of caesium and sodium ions into vanadium oxide bronze nanowires for high-performance aqueous zinc-ion batteries

“…6,7 To address the above drawbacks, aqueous metal-ion batteries have attracted extensive interest as safe and cheap candidates, involving magnesium (Mg), calcium (Ca) and aluminium (Al). [8][9][10][11][12][13][14] Among numerous alternatives, massive efforts have been dedicated to the development of aqueous zinc-ion batteries (AZIBs) due to the intrinsic advantages of metallic Zn anodes, such as a high theoretical capacity (820 mA h g À1 ) and suitable electrode potential (0.763 V vs. a standard hydrogen electrode). [15][16][17][18][19][20] Despite the feasible compatibility of metallic Zn anodes with weak acid aqueous electrolytes enabling aqueous zinc-ion batteries to possess competitive performance, the exploration of such cathode materials still faces challenge to boost the energy density and cycling durability in regard to the strong electrostatic interaction between intercalated Zn 2+ ions and the lattice frameworks of cathode materials as well as the sluggish diffusion kinetics of Zn 2+ ions in the narrow insertion space.…”

“…6,7 To address the above drawbacks, aqueous metal-ion batteries have attracted extensive interest as safe and cheap candidates, involving magnesium (Mg), calcium (Ca) and aluminium (Al). 8–14…”