Effects of Anion Carriers on Capacitance and Self‐Discharge Behaviors of Zinc Ion Capacitors

Abstract

Pseudocapacitive behavior and ion hybrid capacitors can improve the energy density of supercapacitors, but research has only considered the reaction of cations during the electrochemical process, leading to a flawed mechanistic understanding. Here, the effects of various anions carriers on the electrochemical behaviors of titanium nitride‐based zinc ion capacitor (Zn‐TiN capacitor) were explored. DFT calculations revealed the stable structure of TiN‐SO4 after adsorbed process, enabling SO42− participate in the electrochemical process and construct a two‐step adsorption and intercalation energy storage mechanism, improving the capacitance and anti‐self‐discharge ability of the Zn‐TiN capacitor, which delivered an ultrahigh capacitance of 489.8 F g−1 and retained 83.92 % of capacitance even after 500 h resting time. An energy storage system involving anions in the electrochemical process can improve capacitance and anti‐self‐discharge ability of ion hybrid capacitors.

Compacting Electric Double Layer Enables Carbon Electrode with Ultrahigh Zn Ion Storage Capability

“…Aqueous zinc ion hybrid supercapacitors (ZHSCs), storing charges respectively through fast ionic adsorption/desorption on carbon cathode and plating/stripping on zinc anode, can work at high rates and deliver outstanding lifespan. [1][2][3][4][5][6][7] Taking advantages of the cost-effectiveness and environmental-friendless nature of carbon and zinc, the expanding use of ZHSCs has attracted significant attention in a growing set of practices, especially for building energy-bursting equipment. [8][9][10][11][12][13] For example, based on commercial active carbon cathode, Kang et al developed high-performance ZHSC with a capacity of 121 mAh g À 1 (corresponding to an energy density of 84 Wh kg À 1 ) and 91 % capacity retention was achieved after 10 000 continuous cycling.…”

“…Aqueous zinc ion hybrid supercapacitors (ZHSCs), storing charges respectively through fast ionic adsorption/desorption on carbon cathode and plating/stripping on zinc anode, can work at high rates and deliver outstanding lifespan [1–7] . Taking advantages of the cost‐effectiveness and environmental‐friendless nature of carbon and zinc, the expanding use of ZHSCs has attracted significant attention in a growing set of practices, especially for building energy‐bursting equipment [8–13] .…”

An Edible and Nutritive Zinc-Ion Micro-supercapacitor in the Stomach with Ultrahigh Energy Density

“…For the zinc anode, as shown in Figure b, a series of peaks located at 36.8, 39.4, 43.6, 54.5, and 70.3° belong to (002), (100), (101), (102), and (103), respectively, of the zinc species. At the fully charged state, zinc ions in the electrolyte receive electrons to form Zn nanosheets which are uniformly dispersed on the surface of zinc foil (Figure S14c), indicating that the Zn deposition process occurs. , The successful formation of hierarchical structure on the Zn anode provides sufficient contact area between the electrode and electrolyte ions, which may help to improve ion diffusion kinetics. At the fully discharged state, part of the Zn nanosheet loses electrons and converts to zinc ions to dissolve into electrolyte (Figure S14d).…”

“…This can be explained by the "static electricity−immune mechanism". 40,41 To further evaluate the utility of the e-ZMSC, two devices are assembled in series and wrapped in plastic wrap to avoid electrolyte failure caused by a large amount of water loss, thus affecting performance. After standing for 14 h in ambient conditions, the e-ZMSCs can still drive a red light-emitting diode (LED) (voltage = 2.0−2.2 V, current = 20 mA) (Figure 2g), well demonstrating the high capacitance and excellent self-discharge resistance for satisfying the voltage threshold of commercial electronics.…”

Recent developments in zinc metal anodes, cathodes, and electrolytes for zinc-ion hybrid capacitors

“…8f–h). 154 Other than simple oxides and sulphides, a composite of bimetallic chalcogenide with carbon-based material was also studied as an effective electrode material for ZIC. Patil and co-workers synthesized NbMo 6 S 8 /N-doped carbon composite cathode material to evaluate its performance in a ZIC with Zn anode and a modified aqueous Zn-electrolyte.…”