Carbon‐Based Materials for a New Type of Zinc‐Ion Capacitor

Abstract

Zinc-ion capacitors (ZICs), as a new type of electrochemical energy storage (EES) device with great development prospects, have garnered considerable attention because they integrate the advantages of high-energy zinc-ion batteries and highpower supercapacitors to meet people's demand for low-cost, long-term durability and high safety. Nevertheless, the investigation of ZICs remains in its infancy, and many problems need to be resolved. In particular, the challenge caused by the finite ion adsorption capacity of carbon-based electrodes gravely limits the energy density of ZICs. Consequently, determining how to design a new type of carbon material with a high energy density without affecting its inherent power and longterm durability has become a key issue. This Review systematically summarizes the research progress in the preparation, morphology, composition, and electrochemical properties of various carbon-based materials used in ZICs in recent years, focusing on the charge-storage mechanism. Current challenges and future opportunities in the application of carbon-based materials in ZICs are also presented. This Review will help researchers understand ZICs further and develop new EES systems to satisfy the needs of quickly expansion electric automobiles and intelligent electronic device.

A Template‐Engaged, Self‐Doped Strategy to N‐Doped Hollow Carbon Nanoboxes for Zinc‐Ion Hybrid Supercapacitors

“…[13e,14,15] Besides, porous carbon materials have distinct superiority over electrode materials due to large specific surface areas, good electrical conductivity, easy adjustability of pore size, excellent stability. [14,15] Meanwhile, the elaborate design of nanostructures could achieve an efficient dynamic process considering that it can promote mass migration and charge transfer during the whole electrochemical process. [15b,16] Hence, various nanostructures, such as carbon quantum dots, carbon nanotube, carbon nanofiber, graphene, carbon hollow nanospheres, and nano-bowl, etc.…”

Polypyrrole nanoparticles embedded nitrogen-doped graphene composites as novel cathode for long life cycles and high-power zinc-ion hybrid supercapacitors

“…Impressively, this rGO4/PPy1 cathode for ZIHSCs can achieve an energy density in the range of 232.50-110.40 W h kg À1 at power density values in the range of 160-11 200 W kg À1 , showing much higher values than those of commercial zinc batteries and conventional capacitors. Our report of a ZIHSC with a rGO4/PPy1 cathode is also superior to many previous reports of similar cathode-based materials, such as hollow carbon spheres (59.7 W h kg À1 at 447.8 W kg À1 ), 30 kelp activated carbon (111.5 W h kg À1 at 1300 W kg À1 ), 31 graphene (106.3 W h kg À1 at 31 W kg À1 ), 32 graphene/MWCNTs (137 W h kg À1 at 199 W kg À1 ), 32 graphene/MXene (34.9 W h kg À1 at 279.9 W kg À1 ), 33 PPy (112 W h kg À1 at 360 W kg À1 ) and nanostructured PPy (64 W h kg À1 at 1170 W kg À1 ), 34 PPy/carbon (164 W h kg À1 at 390 W kg À1 ), 35 PANI/ molecular-decorated carbon cloth (185.7 W h kg À1 at 9742 W kg À1 ) 12 and so on 10,21,36 (see more details in Table S1 †). Thus, our results suggest that the optimized N-rGO4/PPy1 cathode can be well utilized for ZIHSCs.…”

“…14 In fact, carbon-based material cathodes generally store Zn 2+ only by electro-absorption, with a capacity limitation of 80-120 mA h g À1 . 10 Furthermore, the stacking of graphene sheets during their fabrication results in a decrease in surface area, which limits the Zn 2+ storage energy of graphene. To enhance its electrochemical storage, many researchers have taken advantage of the use of heteroatom (i.e., boron, nitrogen, sulfur, and phosphorus) doping on carbon to boost the electrochemical properties of graphene, leading to an enhancement in its surface redox reactions and functional conductivity.…”

Expanded Graphite-Based Materials for Supercapacitors: A Review

“…When compared to rechargeable batteries, supercapacitors exhibit quicker charging and discharging (supercapacitors: 1–10 s vs. battery: 0.5–5 h), higher power density (supercapacitors: 500–10,000 W kg −1 vs. battery < 1000 W kg −1 ), remarkable longer life (supercapacitors > 500,000 h vs. battery: 500–1000 h), together with safer operation [ 2 , 11 , 12 , 13 ]. However, the low energy density of supercapacitors (supercapacitors: 1–10 W h kg −1 vs. battery: 10–100 W h kg −1 ) is a major challenge to the further development of supercapacitors [ 2 , 11 , 14 , 15 , 16 , 17 , 18 ]. To overcome this, most studies have focused on developing high-performance supercapacitor electrode materials.…”

“…Asymmetric supercapacitors combine two electrode materials with a good potential window [ 23 , 24 ]. As a new type of supercapacitor, hybrid supercapacitors are composed of battery-type negatives (electrochemical insertion or conversion) and capacitive positives (physical adsorption) and have many characteristics of supercapacitors [ 14 , 15 , 16 , 17 , 18 ].…”