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[Display omitted] • Two basic design strategies for 3D COFs: high valency and functionalization. • 3D COFs: building blocks, topology, linkage, and PSM strategy. • Applications in adsorption and separation, catalysis, stimulus response, conduction and energy storage. • The challenges and opportunities are proposed for future research. Covalent organic frameworks (COFs) are a class of porous crystalline organic materials. The dynamic chemistry of covalent bonding and the applications of COFs have made great progress already. Three-dimensional (3D) COFs have attracted much attention in recent years because of their more diverse spatial structures and interconnected pore properties. High valency and functionalization are two key strategies of 3D COFs design, including the development of building blocks, topology, linkage and post synthetic modification strategy. As a result, the diversity of COF spatial structures is significantly extending and various applications in energy, environment, biology and chemical catalysis are developing. In this review, we summarized the recent articles about 3D COFs in the field of framework design, function development and applications, and put forward the critical strategies and comment, the future perspectives of the field are also prospected. [ABSTRACT FROM AUTHOR]

Although tremendous efforts have been devoted to manganous oxide (MnO)-based hybrid electrode materials, the rational design and facile preparation of high-performance MnO hybrid supercapacitors are still full of challenges, due to the inevitable agglomeration and limited stability of MnO within carbon matrixes. In this work, we developed a direct one-pot polymerization method to synthesize a series of Mn ion doped polylevodopa [P(L- DOPA)] synthetic melanin nanoparticles (Mn@SMNPs) for further transforming into small-sized hybrid carbon nanoparticles (MnO@CNPs, 20–80 nm) consisting of many stable Mn-related chemical bindings (C–N–Mn). The obtained MnO@CNPs electrode materials with physically spatial protection and well distribution of MnO could display high specific capacitance values (e.g., 545 F g−1 at 0.5 A g−1 in 6 M KOH electrolyte) within a wide operation voltage of 1.3 V. This work will continue to provide an inspiration towards the fabrication of the next-generation of high-performance synthetic melanin-based energy storage materials and devices. [Display omitted] ● MnO@CNPs were prepared through a facile one-pot fabrication strategy with small size and high MnO doping content. ● The obtained MnO@CNPs with physically protection showed a well distribution of MnO. ● The stable C–N–Mn chemical binding structure facilitates the stabilization of MnO during the charging and discharging. [ABSTRACT FROM AUTHOR]

[Display omitted] • High P-doped (9.24 at%) thick carbon electrodes (CW-P) by phytic acid treatment. • SSC exhibits high capacitance of 4.7F cm−2/206.5F g−1 at 1.0 mA cm−2. • Excellent capacitance retention of 90.5% after 20 000 cycles (@20 mA cm−2). • High energy density up to 0.94 mW h cm−2 (41.2 Wh kg−1). • High power density up to 0.6 mW cm−2 (26.3 W kg−1). Keeping outstanding electrochemical performance under high mass loading is critical to develop functional thick electrodes. Here, we report a high phosphorus-doped wood-derived carbon thick electrode for supercapacitor via phytic acid treatment, which can form hydrogen bonds with cellulose molecules in the wood. The content of phosphorus reaches up to 9.24 at% in carbonized wood with P-doping (CW-P-9.24), higher than most previously reported P-doped carbonaceous materials. CW-P-9.24 electrode (800 μm, 17.17 mg cm−2) exhibits greatly improved electrochemical performance, especially in energy density and cyclic stability. Significantly, the symmetrical supercapacitor device exhibits high areal and specific capacitance of 4.7 F cm−2 and 206.5 F g−1 at 1.0 mA cm−2 with prominent retention of 90.5% through the long-term cycling at 20 mA cm−2 for 20,000 cycles, and 0.94 mW h cm−2 (41.2 Wh kg−1) at power density of 0.6 mW cm−2 (26.3 W kg−1), and possesses excellent volumetric capacitance and energy density of 29.3 F cm−3 and 5.8 Wh cm−3, respectively. The outstanding performance can be attributed to the excellent hierarchical structure, low tortuosity, and high phosphorus doping with fast accessible channels at high current density. The extraordinary performance of CW-P has been elucidated by density functional theory calculations, which confirm the enhanced activity by P-doping. These results demonstrate that the CW-P electrode is promising for practical application in energy storage devices and encourage more investigations for thick electrode. [ABSTRACT FROM AUTHOR]

[Display omitted] • The effect of electrode thickness on the supercapacitance performance is studied. • Bass wood with hierarchical pores is easy processed to thick electrode. • The thick electrodes have high specific/areal/volumetric energy/power densities. • The SSC shows excellent cycling performance of 81% (20 mA cm−2, 15 000 cycles). The practical application of energy storage device requires high areal/volumetric energy density. One of the strategies is to design bulk electrode with hierarchical porous structure for the application of supercapacitor. Significantly, the energy storage electrochemical performance of the bulk electrode is highly influenced by the pore structure regulation and electrolyte infiltration. Therefore, it is necessary to design thick electrodes with proper pore structures and investigate the effect of thickness on the supercapacitance performance. In this work, bass wood is selected as the carbon source of electrode because of its hierarchical porous structure and easy processing into different thicknesses. The wood-derived carbon thick electrode with a thickness of 1.532 mm (CWT1.532) presents the best supercapacitance performance. Such electrode possesses a high active material loading of 54.75 mg cm−2. The symmetrical supercapacitor from CWT1.532 electrode displays remarkable specific capacitance of 65 F g−1 and areal/volumetric capacitance of 0.846 F cm−2 and 2.67 F cm−3 at 1.0 mA cm−2, respectively. It also exhibits mass/areal/volumetric power densities of 38.47 W kg−1, 500 mW cm2 and 1580 mW cm−3 as well as the corresponding energy densities of 9.04 Wh kg−1, 117.5 mWh cm−2 and 0.374 mWh cm−3, respectively. Moreover, the symmetrical supercapacitor shows an attractive cycling stability with a supercapacitance retention of 81.48% at 20 mA cm−2 even after 15 000 long-term cycles. This work provides an essential understanding about the effect of different thicknesses on the thick electrode-assembled supercapacitance and inspires future practical application in other energy storage areas. [ABSTRACT FROM AUTHOR]