A ZIF‐8 Host for Dendrite‐Free Zinc Anodes and N,O Dual‐doped Carbon Cathodes for High‐Performance Zinc‐Ion Hybrid Capacitors

Abstract

Zn is a promising anode for aqueous energy storage owing to it intrinsic superior properties such as large capacity, abundant reserves, low potential and safety. But, the growth of dendrites during charge and discharge leads to a decrease in reversibility. In addition, further development of zinc‐ion hybrid capacitors (ZICs) is seriously challenging because of the lack of an exceptional cathode. Herein, we use ZIF‐8 annealed at 500 °C (annealed ZIF‐8) as a host material for stable and dendrite‐free Zn anodes. Utilization of annealed ZIF‐8 results in dendrite‐free Zn deposition and stripping as a result of its porous construction, which contains trace Zn. Furthermore, we firstly proposed innovative N,O dual‐doped carbon which was designed by the derived ZIF‐8 (ZIF‐8 derived C) as cathode for high‐energy and power‐density ZICs. The new ZIC assembled by Zn@annealed ZIF‐8 anode and ZIF‐8 derived C cathode provides a capacity of 135.5 mAh g−1 and an energy density of 108.4 Wh kg−1 with a power density of 800 W kg−1 at 1.0 A g−1. In addition, it shows outstanding cycling stability of 91% capacity retention after 6000 cycles at 5.0 A g−1. Moreover, the solid‐state ZICs can drive LEDs and smart watches. This ZIC holds promise for the practical application of supercapacitors.

A Better Zn-Ion Storage Device: Recent Progress for Zn-Ion Hybrid Supercapacitors

“…Subsequently, Zn@ZIF-8-500 anode is coupled with activated carbon cathode to form ZHSCs and delivered an energy density of 140.8 Wh kg −1 as well as splendid longevity up to 20,000 cycles. Similarly, Shen et al employed annealed ZIF-8 as the substrate of dendrite-free Zn anode and Zapien et al deposited the Zn onto the flexible carbon cloth (CC) [98,99]. The combination of electrodeposited Zn and carbon materials enables the composite Zn anode outstanding properties for highperformance ZHSCs.…”

“…Lu et al reported molten salt-assisted synthesis of pitch-derived PCs cathodes for Zn//Cap ZHSCs while Guan et al proposed bamboo-derived PCs cathodes with superb stability when employed in ZHSCs (96% capacity retention after 90,000 cycles) [114,115]. Moreover, Xu et al and Shen et al reported a MOF route for fabricating PCs electrode materials, the ZIF-8-derived PCs presented an splendid performance of 225 mAh g −1 at 0.1 A g −1 and remained 135.5 mAh g −1 at 1 A g −1 [98,116]. As depicted in Fig.…”

“…employed annealed ZIF-8 as the substrate of dendrite-free Zn anode and Zapien et al . deposited the Zn onto the flexible carbon cloth (CC) [ 98 , 99 ]. The combination of electrodeposited Zn and carbon materials enables the composite Zn anode outstanding properties for high-performance ZHSCs.…”

“…and Shen et al . reported a MOF route for fabricating PCs electrode materials, the ZIF-8-derived PCs presented an splendid performance of 225 mAh g −1 at 0.1 A g −1 and remained 135.5 mAh g −1 at 1 A g −1 [ 98 , 116 ]. As depicted in Fig.…”

Zinc‐ion hybrid supercapacitors: Design strategies, challenges, and perspectives

“…The interaction of electrodeposited zinc and substrates or hosts is also crucial for high-performance zinc anodes. [83,84,109] Leng et al [83] prepared a modified CC with pregrown ZIF-8 (CC/ZIF-8) as the substrate for zinc formation. Dendrite-free ZHSCs were effectively built using CC/ZIF-8, because the ZIF-8 lowers the nucleation barrier of zinc, allowing for quick and uniform Zn formation.…”