Electrochemical Zinc Ion Capacitors: Fundamentals, Materials, and Systems

Abstract

An electrochemical zinc ion capacitor (ZIC) is a hybrid supercapacitor composed of a porous carbon cathode and a zinc anode. Based on the low‐cost features of carbon and zinc metal, ZIC is a potential candidate for safe, high‐power, and low‐cost energy storage applications. ZICs have gained tremendous attention in recent years. However, the low energy densities and limited cycling stability are still major challenges for developing high‐performance ZICs. First, the energy density of ZIC is limited by the low capacitance of porous carbon cathodes. Second, aqueous electrolytes induce parasitic reactions, which results in limited voltage windows and poor cycling performances of ZICs. Third, the poor stabilities and low utilization of zinc anodes remain major challenges to develop practical ZICs. This review summarizes the recent progress in developing ZICs and highlights both the promising and challenging attributes of this emerging energy storage technology. Future research directions are proposed for developing better, lower cost, and more scalable ZICs for energy storage applications.

Revisiting Charge Storage Mechanism of Reduced Graphene Oxide in Zinc Ion Hybrid Capacitor beyond the Contribution of Oxygen‐Containing Groups

“…Lately, Yin and co‐workers fabricated zinc ion hybrid capacitor with an oxygen‐rich carbon cathode and revealed additional capacitance deriving from the redox reactions of oxygen‐containing groups. [ 29 ] Similar conclusion was achieved by Shao et al. They demonstrated the dependence of electrolyte wettability and electric conductivity on surface groups and identified the critical roles played by carboxyl and carbonyl for improving the charge storage capability of rGO.…”

“…Cyclic voltammetry (CV) was carried out to evaluate the electrochemical behavior of GO, rGO‐200, and rGO‐500 at 10 mV s −1 within a stable voltage window of 0.01–1.8 V. [ 28,36–40 ] As shown in Figure a, in comparison with GO and rGO‐500, rGO‐200 displays the most prominent redox peaks near 0.9/1.2 V at 10 mV s −1 attributable to the conversion between CO and COH. [ 29,41–43 ] Correspondingly, rGO‐200 also shows the longest charge/discharge time in the GCD profiles at 0.5 A g −1 (Figure 2b), manifesting the highest specific capacitance. Electrochemical impedance spectroscopy (EIS) was tested at open‐circuit potential (Figure 2c).…”

Controlled Deposition of Zinc‐Metal Anodes via Selectively Polarized Ferroelectric Polymers

“…In this regard, developing supporting stationary energy‐storage systems to ensure renewable energy's stable and continuous output becomes an important research direction for scientists and enterprises. [ 1 ] Lithium‐ion batteries (LIBs), as the dominant technology in the current battery market, are widely used in various applications, ranging from electric cars to portable intelligent electronics. However, LIBs are not an ideal candidate for stationary energy‐storage systems due to the limited lithium resources and high cost of raw materials.…”

N, P, and S co-doped 3D porous carbon-architectured cathode for high-performance Zn-ion hybrid capacitors

“…This is primarily attributed to the use of commercial active carbon as a capacitor-type cathode, which displays unsatisfactory performance because of relatively low active sites and adsorbed capacity. 7,8 It is therefore of critical signicance to improve the ZIHC electrode performance by designing a carbon material with high capacity, high specic surface area and multiple active sites.…”