Search

[Display omitted] • Nickel cobalt layered double hydroxide regulated by fungus bran-derived carbon dots are firstly synthesized. • Carbon dots are used for the adjustment of 2D nanosheets to 3D flower-like spheres. • The spherical morphology provides more electro-active sites. • An asymmetric supercapacitor device shows higher energy density. 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−1 at 1 A g−1) and a great rate capability, which are two times higher than those of the NCLDH electrode. Additionally, the asymmetric supercapacitor device assembled with the CDs/NCLDH positive electrode and the fungus bran-derived activated carbon (FBC) negative electrode achieves a superior energy density of 52.5 Wh kg−1 at an ultrahigh powder density of 750 W kg−1. With their simple synthesis method and excellent electrochemical performance, the role of the CDs provides new insights for the development of LDHs with improved performance. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. Unlabelled Image • The CZSrG nanocomposites were designed by physical crosslinking and one-step reduction. • The physical crosslinking was binder-free and achieved by hydrogen-bonds. • The hydrogel structure replaced the traditional organic binder PTFE. • The CZSrG had excellent capacitance compared with other CuS electrodes. [ABSTRACT FROM AUTHOR]

Eutectic electrolytes are emerging to be explored to meet the high demand for aqueous zinc‐ion capacitors (AZICs) due to their high electrochemical stability and environmental‐friendly feature. Notably, a large‐scale requirement for a practical AZIC has been addressed to balance decent performance and increase package size. Thus, a "duet‐insurance" eutectic electrolyte (DIEE) is proposed by introducing successively heavy water (D2O) and dimethyl sulfoxide in an aqueous chaotropic Zn salt solution, which hindered the severe irreversibility of Zn anodes compared to that lacking this dual‐solvent protection. For example, the optimal DIEE delivered a high capacitance of 352.9 F g−1 at 0.5 A g−1 and excellent capacitance retention of ≈100% over 30,000 cycles at 2 A g−1 implementing in pouch cells and showing the ability to operate at a low temperature. Besides, experimental (e.g., nuclear magnetic resonance spectroscopy, Raman spectroscopy, electric double‐layer capacitance, etc.) and theoretical techniques (e.g., molecular dynamics simulation, density functional theory) illustrate the vital presence of contact ion pairs and aggregates ion species. Ultimately, this efficient DIEE system employing "duet‐insurance" protections provides a promising direction for designing novel eutectic electrolytes for AZICs chemistries. [ABSTRACT FROM AUTHOR]

The brain‐storm of designing low‐cost and commercialized eutectic electrolytes for zinc (Zn)‐based electrochemical energy storage (ZEES) remains unresolved and attractive, especially when implementing it at low temperatures. Here, we report an appealing layout of advancing chlorine‐functionalized eutectic (Cl‐FE) electrolytes via exploiting Cl anion‐induced eutectic interaction with Zn acetate solutions. This novel eutectic liquid shows high affinity to collaborate with 1,3‐dioxolane (DOL) and is prone to constitute Cl‐FE/DOL‐based electrolytes with a unique inner/outer eutectic solvation sheath for the better regulation of Zn‐solvating neighboring and reconstruction of H‐bonding. The side reactions are effectively restricted on Zn anodes and a high Coulombic efficiency of 99.5 % can be achieved over 1000 cycles at −20 °C with Zn//Cu setups. By prototyping scale‐up Zn‐ion pouch cells using the optimal eutectic liquid of 3ZnOAc1.2Cl1.8‐DOL, we obtain improved electrochemical properties at −20 °C with a high capacitance of 203.9 F g−1 at 0.02 A g−1 in a range of 0.20–1.90 V and long‐term cycling ability with 95.3 % capacitance retention at 0.2 A g−1 over 3,000 cycles. Overall, the proposal of ideal Cl‐FE/DOL‐based electrolytes guides the design of sub‐zero and endurable aqueous ZEES devices and beyond. [ABSTRACT FROM AUTHOR]

The brain‐storm of designing low‐cost and commercialized eutectic electrolytes for zinc (Zn)‐based electrochemical energy storage (ZEES) remains unresolved and attractive, especially when implementing it at low temperatures. Here, we report an appealing layout of advancing chlorine‐functionalized eutectic (Cl‐FE) electrolytes via exploiting Cl anion‐induced eutectic interaction with Zn acetate solutions. This novel eutectic liquid shows high affinity to collaborate with 1,3‐dioxolane (DOL) and is prone to constitute Cl‐FE/DOL‐based electrolytes with a unique inner/outer eutectic solvation sheath for the better regulation of Zn‐solvating neighboring and reconstruction of H‐bonding. The side reactions are effectively restricted on Zn anodes and a high Coulombic efficiency of 99.5 % can be achieved over 1000 cycles at −20 °C with Zn//Cu setups. By prototyping scale‐up Zn‐ion pouch cells using the optimal eutectic liquid of 3ZnOAc1.2Cl1.8‐DOL, we obtain improved electrochemical properties at −20 °C with a high capacitance of 203.9 F g−1 at 0.02 A g−1 in a range of 0.20–1.90 V and long‐term cycling ability with 95.3 % capacitance retention at 0.2 A g−1 over 3,000 cycles. Overall, the proposal of ideal Cl‐FE/DOL‐based electrolytes guides the design of sub‐zero and endurable aqueous ZEES devices and beyond. [ABSTRACT FROM AUTHOR]

Binder use results in an expansion of the dead volume of the active material and a decline in the active sites, which will lead to a decrease in the electrochemical activity of the electrode. Therefore, the construction of electrode materials without the binder has been the research focus. Here, a novel ternary composite gel electrode without the binder (reduced graphene oxide/sodium alginate/copper cobalt sulfide, rGSC) were designed using a convenient hydrothermal method. Benefiting from the dual-network structure of rGS via the hydrogen bonding between rGO and sodium alginate not only better encapsulates CuCo 2 S 4 with high pseudo-capacitance, but also simplifies the electron transfer path, and reduces the electron transfer resistance, which leads to a remarkable enhanced electrochemical performance. The rGSC electrode exhibits a specific capacitance of up to 1600.25 F g−1 when the scan rate is 10 mV s−1. The asymmetric supercapacitor was constructed with rGSC and activated carbon as the positive and negative electrode in a 6 M KOH electrolyte. It has a large specific capacitance and high energy/power density (10.7 Wh kg−1/1329.1 W kg−1). This work proposes a promising strategy for designing gel electrodes for higher energy density and larger capacitance without the binder. The binder- and conductor-free 3D dual-network gel electrode with encapsulated cobalt sulfide copper was constructed by a simple cross-linking and one-step reduction method, which not only possesses large capacitance, but also has potential use in supercapacitors. [Display omitted] • The 3D dual-network of the rGSC gel electrode binder-free was prepared. • The capacitance of the rGS gel electrode encapsulated with CoCu 2 S 4 is vastly boosted. • The rGSC gel electrode possessed a specific capacitance as high as 1600.25 F·g−1. [ABSTRACT FROM AUTHOR]

In this study, to improve the soil amendment performance of film materials, composite films with the adjustable number of layers and controlled slow-release time were prepared using sodium alginate (SA), chitosan (CS) and activated charcoal (AC) as raw materials. The prepared multilayer films exhibited a wide pH response range and excellent slow-release time. The cumulative release of humic acid (HA) increased from 19.87 ± 0.98% to 66.72 ± 1.06% with increasing the pH from 4.0 to 10.0 after 700 h of slow-release. In addition, after 50 d of remediation in red soil, plantation soil, and saline soil, the NH 4 +-N, Olsen-P, Olsen-K, and organic matter contents in the three soils were increased by 2.91–28.62 mg/kg, 46.97–70.43 mg/kg, 55.89–77.01 mg/kg, and 12.47–22.52 g/kg, respectively, and were able to provide sustained crop growth promotion effect. This study demonstrates the promising application of multilayer film in soil remediation and agricultural production. [Display omitted] • Layer-controlled film was prepared by self-assembly method. • Multilayer structure realized the controllability of slow-release time. • The film exhibited a wide pH response used to remediate different soils. • Natural biomass materials provide excellent biodegradability. [ABSTRACT FROM AUTHOR]

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. Image 1 • Corncob-derived porous carbon (CCAC) served stable MOF support. • CCAC simultaneously served as an organic pollutant buffer-reservoir. • MOF/CCAC showed high efficient photodegradation of multiple pollutants. • Optimized MOF/CCAC showed higher charge separation and lower carrier recombination rates. [ABSTRACT FROM AUTHOR]