Strongly Coupled Pyridine‐V₂O₅·nH₂O Nanowires with Intercalation Pseudocapacitance and Stabilized Layer for High Energy Sodium Ion Capacitors

Abstract

Developing pseudocapacitive cathodes for sodium ion capacitors (SICs) is very significant for enhancing energy density of SICs. Vanadium oxides cathodes with pseudocapacitive behavior are able to offer high capacity. However, the capacity fading caused by the irreversible collapse of layer structure remains a major issue. Herein, based on the Acid–Base Proton theory, a strongly coupled layered pyridine‐V2O5·nH2O nanowires cathode is reported for highly efficient sodium ion storage. By density functional theory calculations, in situ X‐ray diffraction, and ex situ Fourier‐transform infrared spectroscopy, a strong interaction between protonated pyridine and VO group is confirmed and stable during cycling. The pyridine‐V2O5·nH2O nanowires deliver long‐term cyclability (over 3000 cycles), large pseudocapacitive behavior (78% capacitive contribution at 1 mV s−1) and outstanding rate capability. The assembled pyridine‐V2O5·nH2O//graphitic mesocarbon microbead SIC delivers high energy density of ≈96 Wh kg−1 (at 59 W kg−1) and power density of 14 kW kg−1 (at 37.5 Wh kg−1). The present work highlights the strategy of realizing strong interaction in the interlayer of V2O5·nH2O to enhance the electrochemical performance of vanadium oxides cathodes. The strategy could be extended for improving the electrochemical performance of other layered materials.

Chrysanthemum-like Polyaniline-Anchored PANI0.22·V2O5·0.88H2O-Hybridized Cathode for High-Stable Aqueous Zinc-Ion Batteries

“…After the introduction of PANI, the absorption peak at 3212 cm –1 corresponded to the stretching vibration mode of the N–H bond, while the peaks at 1570, 1301, and 1472 cm –1 are assigned to the stretching vibrations of the CC, C–N, and CN groups, respectively. Besides, the peaks at 1133 and 1242 cm –1 are related to the C–H bond of the quinonoid- and benzenoid-ring, respectively . These spectroscopic results evidence the formation of protonated polyanilines.…”

Pseudocapacitive Vanadium‐based Materials toward High‐Rate Sodium‐Ion Storage

“…Improved electronic conductivity is commonly achieved through composite structures with carbon. For instance, cathodes of doped pyridine‐V 2 O 5 ·nH 2 O nanowires [ 36 ] (σ electronic = 7.51 S cm −1 ) and bilayered‐V 2 O 5 /CNT with conductive frameworks [ 37 ] (σ electronic = 3.0 S cm −1 ) deliver excellent rate capability at 60 C (1 minute charge–discharge). However, designing materials with intrinsically high electronic conductivity is desirable in EES devices to maintain high‐energy density at high‐power density without the need for high carbon content composite electrodes.…”

“…More recently, a layered pyridine‐V 2 O 5 · n H 2 O nanowire cathode was synthesized using a hydrothermal method. [ 36 ] The pyridine‐V 2 O 5 · n H 2 O had an interlayer spacing of ~11.36 Å and its chemical formula was V 2 O 5 ·0.77H 2 O·0.54Pyridine. Compared to pristine V 2 O 5 · n H 2 O, the pyridine‐V 2 O 5 · n H 2 O exhibited a reduction in the average vanadium oxidation state which led to an enhanced electronic conductivity (7.51 vs. 0.047 S cm −1 ).…”

Synthesis and Electrochemical Performance of the Orthorhombic V2O5·nH2O Nanorods as Cathodes for Aqueous Zinc Batteries

“…In this respect, both alkali/alkaline-earth metal ions (Li + , [ 29 ] Na + , [ 30 ] Mg 2+ , [ 31 ] Ca 2+ , [ 32 ] etc.) and polar molecules (water, [ 33 ] pyridine, [ 34 ] etc.) have been adopted to pre-intercalate into the spaces between two bilayers, thus resulting in improved reaction kinetics and cycling stability of vanadium oxides.…”