In Situ Carbon Insertion in Laminated Molybdenum Dioxide by Interlayer Engineering Toward Ultrastable “Rocking‐Chair” Zinc‐Ion Batteries

Abstract

Aqueous zinc-ion batteries (ZIBs) have attracted significant attention due to their intrinsic safety, cost-effectiveness, and environmental friendliness. However, the common zinc metal anode suffers from zinc dendrite formation, self-corrosion, and surface passivation, which impede the further application of aqueous ZIBs. Herein, carbon-inserted molybdenum dioxide (MoO 2 ) materials with laminated structure are designed as novel intercalation-type anodes for ZIBs by combination of interlayer engineering and in situ carbonization of aniline guest in molybdenum trioxide interlayers. The uniform dispersion of carbon layers in laminated MoO 2 not only provide fast transportation paths for electron but also strengthen the framework of MoO 2 , leading to high structural integration during high-rate cycling. Benefiting from the unique structural design, the carbon-inserted MoO 2 electrode exhibits high initial Coulombic efficiency, excellent cycling stability, and outstanding rate capability. Multiple ex situ characterizations reveal its excellent electrochemical stability is derived from reversible intercalation mechanism and ultrastable structural framework. Furthermore, the rocking-chair zinc-ion full battery assembled with the zinc pre-intercalated Na 3 V 2 (PO 4 ) 2 O 2 F cathode presents excellent stability and ultralong lifespan with a high capacity retention of 91% over 8000 cycles.

Dual‐Redox Sites Guarantee High‐Capacity Sodium Storage in Two‐Dimension Conjugated Metal–Organic Frameworks

“…Furthermore, the purpose of quantifying the contribution rate of capacitive effect (k 1 v) and diffusion behavior (k 2 v 1/2 ) to the whole capacity can be achieved by this formula: i = k 1 v + k 2 v 1/2 , where the k 1 and k 2 are obtained by fitting the iv −1/2 and v 1/2 lines. [40,41] As shown in Figure 4c, the shaded area representing the capacitance contribution rate is 63.6% at 0.8 mV s −1 , and the capacitance contribution increases from 45.8% to 76.7% accompanying with the sweep rate increases from 0.2 to 2 mV s −1 (Figure 4d). In addition, the contribution rate of diffusion capacity confirms that HATN-OCu endows better ion diffusion ability than HATN-SCu (Figure 4e).…”

Lithium Storage in Nanodimensional TiO2/Carbon Nanosheet Composites: Implications for Battery Applications

“…Generally, the b values corresponding to the cathodic and anodic peaks in both carbon/TiO 2 NS and carbon/TiO 2 NT composites are close to 1. The results indicate that the main reactions in both carbon/TiO 2 NS and carbon/TiO 2 NT composites that occur at the interface/surface of the composite are capacitance-dominated, , which can be attributed to the interfacial charge storage mechanism between the carbon NS and TiO 2 NS for the carbon/TiO 2 NS composite and the extremely small diameter of the TiO 2 NT ( D = 6.57 nm) and the high surface area of the carbon/TiO 2 NT composite. However, the b values corresponding to the cathodic and anodic peak currents of the carbon/TiO 2 NP are 0.86 and 0.70, indicating a fast pseudocapacitive process on the surface of the NPs and a slow diffusion process still occurs inside the NPs.…”

Interfacial Kinetics Regulation of MoS2/Cu2Se Nanosheets toward Superior High‐Rate and Ultralong‐Lifespan Sodium‐Ion Half/Full Batteries

“…Firstly, the CV curves at different scan rate are displayed in Figure 4a, where the oxidation peak (peaks 1-3) and the reduction peak (peaks 4-6), respectively, shift to higher and lower potentials with the enhancement of the sweep rate from 0.2 to 1.0 mV s À 1 , which is resulted from the enlarged electrode polarization. [40] There is a relationship between the current of these peaks and the sweep rate: i = av b , in which a and b are variables.. [41,42] Generally speaking, the value of b is between 0.5 and 1, which can reflect that the electrochemical behavior of the electrode is controlled by capacitance or diffusion. [43] Figure 4b exhibits that the b values of peaks 1-6 are 0.68, 1, 0.71, 0.74, 0.98, and 0.79, respectively, which suggests the storage of Na + in the electrode is controlled by a hybrid mechanism of capacitance effect and diffusion process.…”