Search

Layered double hydroxides (LDHs) often require the use of carbon materials to improve their stability, conductivity, and specific surface area to accommodate new directions in the development of high-performance energy storage materials. Herein, 2D nickel cobalt layered double hydroxide (NCLDH) nanosheets are regulated to form 3D flower-like spheres by fungus bran-derived carbon dots (CDs) via an in situ growth method. The prepared sample (CDs/NCLDH) shows abundant accessible active sites and favorable electrical conductivity, which is aided by strong interactions between CDs and NCLDH. The optimized CDs/NCLDH exhibits significantly enhanced electrochemical performances, including ultrahigh specific capacitance (2100F g

A low concentration eutectic electrolyte (LCEE) proposed by using N-methyl-2-pyrrolidone (NMP) additive delivered superior cycling ability and excellent compatibility in coin cell and pouch cell prototypes.

In this work, pH-responsive gel spheres for controlled release of humic acid (CSGCHs) were prepared by an integrated instillation technology using a composite material of sodium alginate (SA) and charcoal activated carbon (CAC) as a carrier, and their slow-release performance, pH-responsive performance, and soil amendment performance were investigated. The results showed that the prepared CSGCH was uniform in size with obvious base responsiveness. Soil remediation experiments revealed that CSGCH could play a good role in the remediation of different types of soils. After 50 days of remediation, the content of nutrients and organic matter in the soil increased significantly and the pH and salt content of saline soils decreased by 15.2 and 29.8%, respectively. The plant experiment showed that CSGCH could effectively promote the growth of crops. Therefore, the prepared soil conditioner has a great potential value for improving soil conditions and promoting crop growth in agricultural applications.

Exploring high-efficiency, green, low-cost, and sustainable biomass waste materials to solve energy shortage and environmental contamination issues is still a significant challenge. Herein, self-template corncob porous carbon (CPC) with bifunctions, high oxygen (16.34 at%), and nitrogen content (2.30 at%) was obtained by a simple carbonization-activation method. Benefiting from the high specific surface area, porous structure and high oxygen and nitrogen content of the prepared CPC, the optimal CPC-700-2 exhibited a higher special capacitance of 295.93 F g–1 at the current density of 1 A g–1, good rate capability (170 F g–1 at 50 A g–1), and excellent stability and circularity. Significantly, the CPC-based symmetric supercapacitor demonstrated a high energy density (9.9 Wh kg−1) at a power density of 250 W kg−1, and exceptional cyclic stability. More interestingly, the CPC also has an efficient sewage purification capacity. The adsorption test confirmed that the CPC possesses a higher adsorption capacity and removal rate for Rh B (249.06 mg g–1 and 99.87%). This satisfactory performance provides a potential way for the high value-added utilization of agricultural and forestry waste.

Integrating and utilizing natural resources rationally is an important strategy for sustainable development. Herein, a novel nanoporous carbon material with rime scenery-like support was firstly established, in which waste biomass fungus bran was skillfully selected as the layered structure carbon skeletons for loading carboxymethyl cellulose derived carbon particles. The dual biomass-derived carbon with the aid of activating by KMnO4 has a unique structure and favorable electrical conductivity. The resulting sample also has a high micropore ratio, which is optimum for the formation of double layer in aqueous electrolyte. Profiting from hierarchical nanopore structure and nitrogen self-doping, the optimized carbon electrode exhibited excellent specific capacitance of 407 F g−1 at 0.5 A g−1, remarkable rate characteristic, and superior cycling performance (96.9% remained after 5000 cycles). More importantly, the assembled symmetric supercapacitor exhibited a high energy density of 11.4 Wh kg−1 and outstanding electrochemical performance in aqueous electrolyte, which benefited from well-connected networks and multipath channels. This research realizes the utilization of waste biomass in carbon-based electrodes and offers the basis of preparation method for the next generation of sustainable energy storage devices. The fabricated rime scenery-like nanoporous carbon materials exhibit ultra-high specific capacitance and the symmetric supercapacitor possesses a high energy density and power density.

Conforming to sustainable development trend, natural material cellulose has been extensively studied in the field of energy storage. However, its low conductivity is a huge obstacle to its application in supercapacitors. Integrating nanocellulose as a green binder with conductive materials achieves the efficient use of natural resources. Here, carbon nanotubes (CNTs) were embedded in porous Co3O4 (PCO) dodecahedrons in situ derived from zeolitic imidazolate framework-67 (ZIF-67), for which the morphologies of the composites were considerably remained at the dodecahedron. The main pseudo-capacitive materials are regulated by different amounts of CNTs to modify the morphology and enhance the conductivity. For electrode materials, the charming structure of PCO-CNTs (PCC) with multichannels allows efficient electron transfer, which brings about a competent utilization of redox active sites in PCO. What is more worth mentioning is that the nanocellulose-PCC nanocomposites with good processing properties were used to form binder-free electrodes. Given the fine designed structure and good electrochemical performance, the electrodes were assembled into symmetric supercapacitors, showing high areal capacitance, energy, and power density. The preparation of composites based on PCC and nanocellulose provides a new way to develop sustainable energy storage devices.

Free-standing nanocellulose/ZIF-67 derived porous Co3O4 polyhedron hybrid dual-layer films were layer-by-layer successfully assembled by a water-based paper-making process. Nanocellulose (NFC) not only served as flexible substrate, but also it substituted expensive polymer binders to reduce the cost in the dual-hybrid film electrodes. Besides, the NFC/porous Co3O4 polyhedron composite (NPC) layer replaced the traditional metal current collector to be a free-standing electrode. The flexible NPC-60 film electrode (the ratio of porous Co3O4 polyhedron to NFC component was 60:30) had a higher capacitance (594.8 mF cm−2 at 5 mV s−1 in 6 M KOH) than other samples, and a power density of 799.97 W·kg−1 at the energy density of 18.75 Wh·kg−1. With the increase of NFC content, the hybrid film can be bent and rolled demonstrating that the hybrid film has good flexibility and foldability. This work provides an insight perspective for metal organic framework (MOF)-derived metal oxide powders to form flexible and free-standing supercapacitor electrodes.

To tackle the crisis of fossil energy shortage and global warming, exploring a series of efficient, portable devices for the conversion/storage of clean and renewable energy sources has remained a significant topic. Supercapacitors as an advanced energy storage device have the properties of portability and stable performance, electrode materials especially flexible electrode materials as important components of supercapacitors have drawn great attention in various emerging fields such as portable, wearable electronics and memory materials. Based on high aspect ratios, specific surface areas, porosity, mechanical properties and excellent flexibility, natural polysaccharide cellulose and its derivatives have become promising building polymers for flexible electrode materials. In view of poor electrical conductivity and low areal capacitance, the compound modification of cellulose flexible materials and the corresponding application in flexible electrodes are reviewed. To further illustrate their versatile properties and performances, cellulose-based flexible electrolytes and membranes are summarized with detailed examples. Overall, this review covers recent advances regarding cellulose-based flexible materials for different components including electrodes, electrolytes and membranes used in supercapacitors and expects to provide references for further research of this promising material.

CuS/ZnS/sodium alginate/reduced graphene oxide nanocomposites (CZSrG) were prepared by physical crosslinking followed by one-step reduction and were justified as green binder-free hydrogel high-capacitance electrodes. The physical crosslinking was realized simply through the hydrogen-bond interaction between sodium alginate (SA) and graphene oxide (GO), avoiding the usage of traditional Ca2+ crosslinking agent. The hydrogel structure made of CZSrG possessed the most beneficial effect of avoiding large volume change and increasing cycle stability for supercapacitors. When used as electrode, the specific capacitance of CZSrG was 992 F·g−1 (10 mV·s−1) in a three-electrode system. Furthermore, the fabricated supercapacitors had a specific capacitance of 252.1 F·g−1 (5 mV·s−1), and a power density of 1800 Wh·kg−1 at the energy density of 2.05 Wh·kg−1. Thus, the CZSrG has a favorable electrochemical performance and wide application prospects in supercapacitors.

In this study, carbon dot-sensitized Ti3+ self-doped TiO2 dual-phase (TiO2−x/CDs) composite photocatalytic systems were successfully constructed using a low-temperature hydrothermal method. The TiO2−x photocatalyst showed improved photocatalytic activities for the removal of Cr6+ and RhB under visible light. Remarkably, RhB (10 mg L−1) and Cr6+ (40 mg L−1) solutions were degraded completely in 30 and 120 min, respectively, by the composite photocatalyst (1 g L−1) under visible-light irradiation. These results were much better than those of commercial P25. This fascinating photocatalytic performance was attributed to the improved photogenerated electron–hole separation efficiency from the synergistic effects of rutile and anatase, and the reduced photogenerated charge carrier recombination and facilitated visible-light absorption from the introduced CDs. This study provides a promising approach for the treatment of real wastewater using sunlight.

Metal-organic frameworks (MOFs) are promising for photocatalysis owing to their excellent structure and performance. Unfortunately, poor stability in both aqueous solutions and high temperatures and lack of adsorption centers during reactions limit their practical applications. Herein, a bimetallic MOF anchored corncob calcined derived activated carbon (CCAC) was successfully prepared by a one-step solvothermal method. Benefiting from unique structures and synergetic effect, the porous carbon provided a high specific surface area for stable MOF support and served as an organic pollutant buffer-reservoir, which was advantageous for efficient photocatalytic degradation of organic pollutants. The optimized MOF/CCAC-5 samples possessed excellent visible light degradation rate, i.e., 100% for Rh B, more than 96% for six mixed dyes, and 98% for tetracycline. This prominent photocatalytic activity was caused by active species, including photoelectrons (e-), photo-holes (h+) and superoxide free radicals (•O2-). The transient photocurrent response and electrochemical impedance tests showed that MOF/CCAC-5 exhibited a relatively high charge separation and low carrier recombination rate. Cyclic and simulation experiments indicated high reusability, stability and universality of the composite photocatalysts. These exciting results provide new pathways for the fabrication of MOFs anchored porous carbon materials.