Synergistic effect of K⁺and PANI in vanadium oxide hydration by interlayer engineering boosts the ammonium ion storage

Abstract

Aqueous ammonium-ion (NH 4 + ) hybrid supercapacitor (AA-HSC), as a new type of energy storage device with great potential, is in the initial stage of rapid development. Based on its special energy storage mechanism, exploiting novel NH 4 + -hosting materials is still a great challenge. Herein, vanadium oxide hydration (VOH) tuned by interlayer engineering of K + /PANI co-intercalation, named KVO/PANI, is designed for AA-HSC. Intercalated PANI can shield interaction between NH 4 + and V-O layers to some extent and enlarge interlayer space, which improves the efficiency of reversible NH 4 + (de)insertion. However, K +enhances redox activity and electronic conductivity. The synergistic effect of co-intercalation optimizes intercalation pseudocapacitive behavior during the (de)ammonization process, which is reported in NH 4 + storage for the first time.Theoretical calculations reveal that the lowered electron transport barrier and enhanced electronic conductivity improve NH 4 + kinetics and exhibit high capacitance for charge storage. The KVO/PANI can deliver the specific capacitance of 340 F g −1 at 0.5 A g −1 and retain 177 F g −1 at 10 A g −1 . Pairing with activated carbon, the AA-HSC can achieve a decent energy density of 31.8 Wh kg −1 . This work gives inorganic/organic co-intercalation that can enhance the NH 4 + storage of VOH by interlayer engineering. The strategy can be used to design other materials for aqueous energy storage systems.

A Comprehensive Review of Ammonium Ion Hybrid Supercapacitors: Exploring Recent Breakthroughs and Future Horizons

“…Here, the extraordinary electrochemical performance is attributed to the fast and facile ammonium ion intercalation/deintercalation in the layered structure as well as hydrogen bond formation/breaking, which offers a new paradigm for electrochemical energy storage devices. Inspired by this, Chen and co-workers evaluated the synergistic effect of K + /PANI cointercalation in vanadium oxide hydration by interlayer engineering technique for AIHSs . The intercalation of polyaniline (PANI) serves to partially shield the interaction between NH 4 + ions and vanadium oxide (V–O) layers, which expands the interlayer space and enhances the efficiency of reversible NH 4 + ion insertion and extraction processes.…”

“…Furthermore, compared to proton or hydronium ions, the hydrolysis of ammonium salts results in a moderately acidic or neutral electrolyte atmosphere. This mitigates side reactions such as hydrogen evolution and reduces corrosiveness, making it less detrimental to devices …”

Enhancing ammonium-ion storage in Mo-doped VO2 (B) nanobelt-bundles anode for aqueous ammonium-ion batteries

“…This is because NH 4 + are abundant in nature, lightweight (minimum molar mass 18 g mol −1 ), fast diffusing (smaller hydrated ion size of 3.31 Å), and less corrosive and hydrogen evolution than other cations. 15–19 These excellent properties enable it to be an ideal charge carrier. In view of this, a series of AAIBs have been gradually reported in the literature in recent years.…”

Mn‐doping ensuring cobalt silicate hollow spheres with boosted electrochemical property for hybrid supercapacitors

“…Supercapacitors (SCs) occupy a unique position in the realm of energy storage devices, positioned between batteries and conventional capacitors. They have the advantages of outstanding long cycle life, high instantaneous power, broad operating temperature range, maintenance‐free operation, and environmental friendliness, which have attracted great interest in the past decades all over the world 6–9 . The charge storage mechanism of electrode materials for energy storage is mainly two types, named as electrochemical double‐layer capacitor (EDLC) and redox 10 .…”

“…They have the advantages of outstanding long cycle life, high instantaneous power, broad operating temperature range, maintenance-free operation, and environmental friendliness, which have attracted great interest in the past decades all over the world. [6][7][8][9] The charge storage mechanism of electrode materials for energy storage is mainly two types, named as electrochemical double-layer capacitor (EDLC) and redox. 10 The energy density (E) of SCs is calculated according to the formula E C V = × × 1 2 2 .…”