High‐concentrated non‐flammable electrolytes (HCNFE) in lithium metal batteries prevent thermal runaway accidents, but the microstructure of their solid electrolyte interphase (SEI) remains largely ...unexplored, due to the lack of direct imaging tools. Herein, cryo‐HRTEM is applied to directly visualize the native state of SEI at the atomic scale. In HCNFE, SEI has a uniform laminated crystalline‐amorphous structure that can prevent further reaction between the electrolyte and lithium. The inorganic SEI component, Li2S2O7, is precisely identified by cryo‐HRTEM. Density functional theory (DFT) calculations demonstrate that the final Li2S2O7 phase has suitable natural transmission channels for Li‐ion diffusion and excellent ionic conductivity of 1.2 × 10‐5 S cm‐1.
The native state of solid electrolyte interphase (SEI) has been observed directly using Cryo‐HRTEM. In high‐concentrated non‐flammable electrolytes, SEI forms a uniform laminated crystalline‐amorphous structure that effectively inhibits further reaction between electrolytes and lithium. The stable dual‐layer SEI contributes to higher coulombic efficiency and excellent ionic conductivity.
The key to realize long‐life high energy density lithium batteries is to exploit functional electrolytes capable of stabilizing both high voltage cathode and lithium anode. The emergence of localized ...high‐concentration electrolytes (LHCEs) shows great promise for ameliorating the above‐mentioned interfacial issues. In this work, a lithium difluoro(oxalate)borate (LiDFOB) based nonflammable dual‐anion LHCE is designed and prepared. Dissolving in the mixture of trimethyl phosphate (TMP) /1,1,2,2‐tetrafluoroethyl‐2,2,3,3‐tetrafluoropropylether (D2), the continuously consumption of LiDFOB is suppressed by simply introducing lithium nitrate (LiNO3). Meantime, as most of the TMP molecular are coordinated with Li+, the electrolyte does not show incompatibility issue between neither metal lithium nor graphite anode. Therefore, it demonstrates excellent capability in stabilizing the interface of Ni‐rich cathode and regulating lithium deposition morphology. The Li||LiNi0.87Co0.08Mn0.05O2 (NCM87) batteries exhibit high capacity retention of more than 90% after 200 cycles even under the high cutoff voltage of 4.5 V, 1 C rate. This study offers a prospective method to develop safe electrolytes suitable for high voltage applications, thus providing higher energy densities.
A dual‐anion phosphate‐based nonflammable electrolyte was designed and prepared. Taking advantage of synergistic effect of LiDFOB and LiNO3, the electrolyte shows good compatibility with both high voltage cathode and lithium metal anode; meantime, the continuous consumption of LiDFOB is restrained by LiNO3. Thus, it shows impressive capacity retention of 97.8% after 200 cycles under high cutoff voltage of 4.5 V.
To improve the harmless treatment of high-concentration heavy metals (HMs) in electroplating sludge (ES), this study tried to combine the microwave pyrolysis technology and the addition of municipal ...sewage sludge (MS) to synergistically improve the immobilization of high-concentration HMs in ES. The results showed that the immobilization rate of HMs was less than 75% in ES pyrolysis biochar. Notably, the immobilization rate of HMs up to 98.00% in co-pyrolysis biochar. Finally, it was found by various characterizations that the organic carbon and inorganic minerals in MS played an important role in the immobilization of HMs through physical and chemical effects. HMs reacted with inorganic minerals to form HMs crystalline minerals (e.g., CuCl, Cu2NiSnS4, and NiSi2, ZnS) to realize the immobilization of HMs. The addition of organic carbon was conducive to the formation of biochar with higher carbon crystallinity (ID/IG = 0.96) and larger specific surface area (52.50 m2 g−1), thereby enhancing the physical adsorption to HMs. Meanwhile, the complexation reaction between HMs and functional groups such as -OH, Si-O-Si could also further improve the immobilization of HMs. Therefore, this study provided a technical and theoretical basis for the harmless disposal of waste containing multiple HMs with high-concentrations.
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•Co-microwave pyrolysis immobilizes up to 98% of high-concentration heavy metals.•Heavy metals is immobilized by forming crystalline minerals with inorganic minerals.•The protection of crystalline carbon is conducive to immobilize heavy metals.•The increase of specific surface area and carbon content adsorbs more heavy metals.•Heavy metals combines with the functional groups to achieve their immobilization.
Rechargeable lithium metal batteries are regarded as the “holy grail” of energy storage systems, but their practical applications have long been hindered by poor cyclability and severe safety ...concerns. In this work, we report a fire-retardant localized high-concentration electrolyte consisting of 1.2 M lithium bis(fluorosulfonyl)imide in a mixture of flame-retardant triethyl phosphate/bis(2,2,2-trifluoroethyl) ether (1:3 by mol) for 4-V class lithium metal batteries. This electrolyte enables stable, dendrite-free cycling of lithium metal anodes with high Coulombic efficiency of up to 99.2%. Moreover, it exhibits excellent anodic stability even up to 5.0 V and greatly enhances the cycling performance of lithium metal batteries. A Li||LiNi0.6Mn0.2Co0.2O2 battery using this electrolyte can retain >97% capacity after 600 cycles at 1 C rate (ca. 1.6 mA cm−2), corresponding to a negligible capacity decay of <0.005% per cycle. Therefore, this new electrolyte can enable safe operation of high-energy lithium metal batteries for practical applications.
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•A fire-retardant localized high-concentration electrolyte (LHCE) is demonstrated•The LHCE inherits merits from the HCE but dramatically overcomes disadvantages of HCE•The LHCE largely improves cycling stability and Coulombic efficiency of Li metal anode•The LHCE enables safe and high-performance 4-V class Li||NMC622 batteries
A safe electrolyte for 4-V class lithium metal batteries (LMBs) was reported by diluting a fire-retardant high-concentration electrolyte (HCE) with an electrochemically “inert” and poorly solvating fluorinated ether. Named localized high-concentration electrolyte (LHCE), it inherits the merits from the HCE but dramatically overcomes its disadvantages. The fire-retardant LHCE enables dendrite-free and stable cycling of a Li metal anode with high Coulombic efficiency of up to 99.2% and greatly enhances the cycling stability of Li||NMC622 batteries for more than 600 cycles. The excellent electrochemical performances of the LHCE is ascribed to the well-reserved, locally concentrated solvation structures and its improved interfacial reaction kinetics and stability. These findings open up a new avenue for developing highly stable and safe electrolyte systems for high-energy-density LMBs for practical applications.
A fire-retardant localized high-concentration electrolyte (LHCE) inherits the merits from the high-concentration electrolyte (HCE) (non-flammability, wide electrochemical stability windows etc.) and dramatically overcomes the disadvantages (high viscosity, high cost, poor wettability) of HCE. Its unique properties lead to dendrite-free and high-Coulombic-efficiency cycling of Li metal anode that supports safe 4-V class Li||NMC622 batteries with excellent cycling stability.
•Effective solar concentration of 1291× is demonstrated experimentally.•Concentration >1700 suns is predicted in future work with cooling rig.•The ReflecTech polymer mirror was deemed the best for ...concentrator application.•Maximum optical efficiency was 22.0% for the full experimental setup.
The optical ultra-high concentration ratio levels are still not demonstrated enough due to the high complexity of the associated optical designs offering restricted angular freedom, and the expansive cost that might be required for such a breakthrough. This research proposes a novel optical design of an ultra-high concentrating photovoltaic system that can achieve a geometric concentration of 5831×. The system consists of four flat silicon-on-glass (SOG) Fresnel lenses as primary optics, four reflectors as secondary optics, and four-domed tertiary optical elements (TOE) that will refract the sunlight onto a 5.5×5.5mm2 triple-junction solar cell. A complete proof-of-concept module has been developed, assembled, and tested. The experiments were conducted based on instantaneous and one hour of continuous measurement. The obtained results showed that the system can achieve a higher effective concentration ratio of 1291 suns when deploying ReflecTech polymer compared to aluminium reflective film of 984 suns and PilkingtonOptimirror of 1220 suns. The developed and tested compact ultra-high concentrator photovoltaic system yielded the highest geometrical concentration ratio and the highest effective concentration ratio achieved experimentally.
In the past several decades, anthropogenic changes throughout drainage basins have threatened physical, hydrological and ecological river-to-ocean continuum balances. Dams are one of these ...anthropogenic influences that can seriously affect sediment fluxes to the ocean. Here, we investigate the formation and dispersion of a high-concentration mud suspension (HCMS) at a river mouth due to a tailing dam failure. In November 2015, the Fundão dam (Mariana-MG, Southeast Brazil) failure released approximately 39.2 million m3 of tailings into the Doce River system. The slurry travelled 660 km down to the river mouth, reaching the Atlantic Ocean. Pre- and Post-dam failure surveys were used to investigate temporal and spatial changes in Suspended Particulate Matter (SPM) concentration, seabed sediment grain size and seabed sediment bulk density along the inner shelf. Results indicate that the combination of the tailing dam failure with an extremely dry seasonal condition led to the formation of a HCMS, altering, at least in a short term, the sedimentary processes along the inner shelf, leading to high sedimentation rates and low seabed sediment bulk density. Changes in particle size defined by an increase in clay content, a significant increase in SPM concentration in the inner shelf and a decrease in seabed sediment bulk density were observed as a result of the dam failure. SPM concentrations were higher near the seabed than at the surface, reaching up to 9000 mg/l. The highest SPM concentration measured during a major flood in January 2014 reached around 100 mg/l, The combination of a HCMS with tailings high clay content resulted in low values of seabed sediment bulk density and the formation of fluid mud along the inner shelf. In the first week after the tailings arrival, a 5 cm thick tailing fluid mud was observed. In this stage of bed formation, bed strength is lower, easing particle reentrainment by waves or currents. Thus, tailings could be advected, spreading the impact along the coast.
•The largest tailing dam failure in history directly influenced the formation of high-concentration mud suspension (HCMS) along the inner shelf.•A comparison between pre- and post-dam failure surveys indicated that the HCMS potentialized the formation of a hyperpycnal.•The tailings input to the shelf increased the sediment clay content in 60% and decrease the mud fraction D50 to clay particle size.•High sediment accumulation rates combined with formation of fluid mud with up to 70% in clay content potentialized wave-enhanced sediment flow.•The combination of an anthropogenic-threat and a climate condition, triggered one of the largest environmental disaster in Brazil.
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•Novel microchannel heat sink(MHS) with serpentine reentrant microchannels(SRM) were developed.•MHS with SRM provided efficient cooling for high concentration photovoltaic(HCPV) ...cells.•MHS with SRM reduced HCPV cell temperatures and enhanced temperature uniformity.•MHS with SRM increased output power and improved electrical efficiencies of HCPV cells.•Larger flow rate induce better thermal and electrical performance of HCPV cells with MHS with SR.
Efficient cooling is critical to reduce cell temperatures of high concentration photovoltaic (HCPV) cells to avoid the output electrical performance degradation and lifetime reduction. In this study, we develop a novel type of microchannel heat sink (MHS) with serpentine reentrant microchannels (SRM) for efficient cooling of HCPV cells. They feature serpentine flow passages with Ω-shaped cross-sectional configurations, which contribute to promote fluid mixing and disrupt the normal development of thermal boundary layers. Thus they are able to provide excellent heat transfer characteristics and highly efficient cooling performance. By the comparison of a fin heat sink, both numerical and outdoor experimental studies were comprehensively conducted to explore the enhancement feasibility of thermal and electrical performance of HCPV cells. Results showed that the SRM reduced the cell temperatures and enhanced the temperature uniformity of HCPV cell module considerably, i.e., it presented cell temperatures of 25-31℃, much smaller than that of 45-63℃ of the fin heat sink. The temperature differences of HCPV cell modules were reduced to be less than 4.4℃. Besides, the output power increased by as high as 115%, and the electrical efficiency increased to 15–20% for the HCPV cell module with serpentine reentrant microchannels. Besides, the HCPV cell module with SRM was also found to induce smaller average cell temperatures and better electrical performance than a module with parallel reentrant microchannels (PRM). Moreover, the effects of flow rate and concentration ratio on the performance of HCPV cells with SRM were also assessed.
Organic carbonyl electrode materials of lithium batteries have shown multifunctional molecule design and high capacity, but have the problems of poor cycling and low rate performance due to their ...high solubility in traditional carbonate‐based electrolytes and low conductivity. High‐performance organic lithium batteries with modified ether‐based electrolyte (2 m LiN(CF3SO2)2 in 1,3‐dioxolane/dimethoxyethane solvent with 1% LiNO3 additive (2m‐DD‐1%L)) and 9,10‐anthraquinone (AQ)/CMK‐3 (AQC) nanocomposite cathode are reported here. The electrochemical results manifest that 2m‐DD‐1%L electrolyte promotes the cycling performance due to the restraint of AQ dissolution in ether‐based electrolyte with high Li salt concentration and formation of a protection film on the surface of the anode. Additionally, the AQC nanocomposite improves the rate performance because of the nanoconfinement effect of CMK‐3 and the decrease of charge transfer impedance. In 2m‐DD‐1%L electrolyte, AQC nanocomposite delivers an initial discharge capacity of 205 mA h g−1 and a capacity of 174 mA h g−1 after 100 cycles at 0.2 C. Even at a high rate of 2 C, its capacity is 146 mA h g−1. This strategy is also used for other organic carbonyl compounds with quinone substructures and they maintain high stable capacities. This sheds light on the development of advanced organic lithium batteries with carbonyl electrode materials and ether‐based electrolytes.
Through the combination of ether‐based electrolyte with high Li salt concentration and LiNO3 additive in addition to 9,10‐anthraquinone (AQ) nanoconfined in CMK‐3, improved cycling and rate performance of AQ is obtained. After 100 cycles at 0.2 C, the discharge capacity and capacity retention can reach 174 mA h g−1 and 84.9%. Even at 2 C, the capacity remains 146 mA h g−1.
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Optimizing the pore structure and its interaction with the electrolytes was vital for enhancing the performance of supercapacitors based on the electrical double layer mechanism. In ...this study, graded porous carbon material (STP) with outstanding properties was prepared by adjusting the activation temperature and KOH dosage in the microwave pyrolysis process of sargassum thunbergii. The results demonstrated that better electrochemical performance was obtained when 1 M NaNO3 was used as electrolyte and STP-800-3 was employed as electrode material, attributed to its excellent specific surface area (SSA) of 2011.8 m2 g-1, high micropore ratio, and the optimal matching degree between micropore size and electrolyte ion diameter. Moreover, the operating voltage window was expanded to 2.0 V in supercapacitors assembled with 6 M NaNO3 high-concentration electrolyte. Simultaneously, the symmetric supercapacitors exhibited a remarkable specific capacitance of 290.0 F g-1, a high energy density of 39.0 W h kg-1, and outstanding capacity retention at 70.9% after 10,000 charge/discharge cycles based on 6 M NaNO3 electrolyte. Consequently, the results provided valuable technical support and theoretical basis to foster progress of novel and high-performance supercapacitors.
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