A dynamic intercalation mechanism in pre-intercalation carbon nanosheets for capacitive deionization cells

Liu, Qi; Zhao, Chengyao; Yuan, Menghan; Liu, Liping; Liu, Xiaohui; Liu, Yujing; Liu, Zhongqiu; Lin, Tong; Ying, Anguo

doi:10.1016/j.desal.2022.115842

Cited by 7 publications

(1 citation statement)

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“…According to the high‐resolution electron microscope (HRTEM) image in Figure 2g,h, the distinct graphene layers in the KPCRP on the edge surface are formed by slit‐like pores that are mostly <1 nm in diameter. [ 35 ] In addition, clear 2D lattice fringe of 4.29 and 2.94 Å can be noted, analogous to the graphite‐like (002) diffraction peak and potassium (113) phase, while PC presents a typical amorphous carbon (Figure S6, Supporting Information). The extended interlayer spacing is related to the K + ‐pre‐intercalation behavior, consistent with the results of the corresponding energy dispersive X‐ray spectroscopy (EDXS) mappings, further demonstrating that the K + uniformly intercalate into the stratified structure (Figure 2i).…”

Section: Resultsmentioning

confidence: 99%

Russian‐Doll‐Like Porous Carbon as Anode Materials for High‐Performance Potassium‐Ion Hybrid Capacitors

Liu

et al. 2022

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as new storage devices by assembling battery-type and capacitor-type electrodes that can meet requirements while deliver high energy at high power without sacrificing their service life. [8] Among them, potassium-ion hybrid capacitors (PIHC) have attracted much attention due to low cost, much higher crustal abundance (CLARKE value) than that of lithium (1.5% > 0.0017%), lower redox potential (−2.93 V K/K + vs SHE; −3.04 V, Li/Li + vs SHE). In particular, hydrated K-ion has the smallest Stokes radius (3.6 Å) compared with Liand Na-ions (4.8 Å and 4.6 Å), demonstrating the great transport properties in aqueous electrolytes. [9][10] More strikingly, aqueous electrolyte rechargeable devices meet the inherent safety and low-cost requirement but suffer from low-capacity issues. Despite some progress, there are still few reports of aqueous potassium-ion hybrid capacitors. [11,12] Recent research attention focused on carbonaceous materials in the field of potassium-ion systems because of their multifarious structural configurations, low cost and excellent physical/chemical stability, sufficient surface area, and excellent electrolyte channels. [13][14][15] On this basis, dual-carbon potassium-ion hybrid capacitors (DC-PIHCs), whose cathode and anode are carbon materials, show the most promising industrial prospects in view of the greatly reduced overall cost of device, competitive K + storage performance and intrinsic long-term cycle stability. [16,17] However, the inescapable fact is that a much larger radius of K + (1.38 Å for K + vs 0.76 Å for Li + ) conspicuously hinders the intercalation behavior of anode materials, leading to the sluggish kinetics and inadequate power density. Even worse, a significant volume expansion (up to 60%) [18] can cause carbon skeletons structural failure and significant capacity fading, which is unfavorable for long lifespan. To tackle these challenges, it is vital to exploit suitable host materials with satisfactory properties for DC-PIHCs.To overcome the aforementioned obstacles, cationic species (Na + , K + , Al 3+ ) pre-intercalation, as one important strategy, enables the carbon anode to accommodate large-sized K + , thus facilitates the charge carrier kinetics and ensure structural stability. [19][20][21] Moreover, porous structure also affects K + migration behavior. [22] As reported, carbon-based anode materials with porous architectures could accommodate huge volume strain, provide good pathways for fast mass transport, and expose Pore-structure design with the sophisticated and pragmatic nanostructures still remains a great challenge. In this work, porous carbon with Russiandoll-like pores rather than traditional single modal is fabricated via a boiling carbonization approach, accompanied by K + -pre-intercalation. The most important internal factor is that alkali can penetrate into the stereoscopic space of layered Malonic acid dihydrazide and the confinement effect leads to the in-depth development of different dimensional pore structures. The oxygenated and nitrogenated surfa...

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Section: Resultsmentioning

confidence: 99%