A Gas‐Steamed MOF Route to P‐Doped Open Carbon Cages with Enhanced Zn‐Ion Energy Storage Capability and Ultrastability

Abstract

Carbon micro/nanocages have received great attention, especially in electrochemical energy‐storage systems. Herein, as a proof‐of‐concept, a solid‐state gas‐steamed metal–organic‐framework approach is designed to fabricate carbon cages with controlled openings on walls, and N, P dopants. Taking advantage of the fabricated carbon cages with large openings on their walls for enhanced kinetics of mass transport and N, P dopants within the carbon matrix for favoring chemical adsorption of Zn ions, when used as carbon cathodes for advanced aqueous Zn‐ion hybrid supercapacitors (ZHSCs), such open carbon cages (OCCs) display a wide operation voltage of 2.0 V and an enhanced capacity of 225 mAh g−1 at 0.1 A g−1. Also, they exhibit an ultralong cycling lifespan of up to 300 000 cycles with 96.5% capacity retention. Particularly, such OCCs as electrode materials lead to a soft‐pack ZHSC device, delivering a high energy density of 97 Wh kg−1 and a superb power density of 6.5 kW kg−1. Further, the device can operate in a wide temperature range from −25 to + 40 °C, covering the temperatures for practical applications in daily life.

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

“…This indicates the existence of PO x groups and P-C units in the carbon skeleton. 21 The S 2p spectrum could be tted to three peaks at 163.9, 165.2 and 168.0 eV, which are associated with S 2p 3/2 of C-S, S 2p 1/2 of C-S and C-SO x -C bonding (Fig. 2i), respectively.…”

“…Zhang et al 17 designed a hollow carbon polyhedron using ZIF-8 as the template, and the as-prepared electrode exhibited good stability. In addition, carbon materials doped with heteroatoms, such as nitrogen (N), 18,19 sulfur (S), 20 phosphorus (P) 16,21,22 and boron (B), 23 have attracted increasing attention due to their excellent performance and potential applications in energy storage. The doping of heteroatoms into carbon materials is benecial to develop more defective sites, which increase active sites for ion de/adsorption and electronic conductivity of the carbon electrode; 24,25 it also improve the wettability of the electrolyte, which is conductive to the electrolyte permeation.…”

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

“…Apart from the commercial AC, many PCs electrode materials can be fabricated through various methods, like template method [111][112][113] and pyrolysis method [108,[114][115][116]. As for the pyrolysis methods, the precursor is a significant part of synthesizing high-quality PC electrode materials.…”

“…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.…”

“…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.…”