Na_(2)SO_(4)-NaCl binary eutectic salt roasting to enhance extraction of lithium from pyrometallurgical slag of spent lithium-ion batteries

Effectively extracting lithium at a relatively low temperature from the slag produced by the pyrometallurgical treatment of spent lithium-ion batteries remains a great challenge,which limits the acquirement of lithium.Herein,we proposed a eutectic system to roast slag at a lower temperature based on sodium sulfate-sodium chloride(Na_(2)SO_(4)-NaCl)binary eutectic salts.The optimal roasting conditions are as follows:the slag was roasted at 750℃with a(SO_(4)^(2-)+Cl^(-))/Li+molar ratio of 5:1 for 120 min.Followed by aqueous leaching 5 min at room temperature with a water/roasted samples mass ratio of 30:1,it can get 97.07%lithium extraction efficiency.

Superior Latent Heat Eutectic Salt Na_(2)CO_(3)-Li_(2)CO_(3)-LiF for Thermal Energy Storage:Preparation and Performance Investigation

In this paper,a novel ternary eutectic salt Na_(2)CO_(3)-Li_(2)CO_(3)-LiF was designed and investigated for concentrated solar power(CSP).The FactSage software was used to predict the composition and eutectic point of Na_(2)CO_(3)-Li_(2)CO_(3)-LiF.The microstructure,thermophysical properties,and thermal stability of eutectic salts were experimentally measured using various analytical methods.With a mass ratio of 57%:32%:11%,the eutectic salt exhibited excellent thermal storage properties with a fusion enthalpy of 413 J/g and a melting point of 426.8℃.The excellent thermal stability of the eutectic salt was reflected by a weight loss of only 0.8% at 600℃.

Cathodic reduction process of Al-Cu-Y alloy in fluoride-oxide eutectic system via molten salt electrolysis

Al-Cu-Y alloys were prepared by molten salt electrolysis in fluoride-oxide system composed of electrolyte（Na3 AlF6-AlF3-LiF-MgF2） and oxide（Al2 O3-CuO-Y2 O3）. Cathodic reduction process of Al2 O3,CuO and Y2 O3 were analyzed by cyclic voltammetry and chronoamperometry. Components and phase composition of alloy samples prepared by potentiostatic electrolysis were characterized by scanning electron microscopy and energy dispersive spectroscopy. The results show that the Al-Cu-Y alloy can be prepared in the AIF3-NaF-5 wt%LiF-5 wt%MgF2（NaF/AlF3 = 2.2, molecular ratio） eutectic system with mixed oxide（Al2 O3-CuO-Y2 O3） through 2 h at the conditions of a temperature of 1208 K, cell voltage3.0 V, cathode current density 0.7 A/cm^2. Al（Ⅲ） and Cu（Ⅱ） ions can be reduced to zero valence Al（0） and Cu（0） directly on carbonaceous electrode surface by instantaneous nucleation, respectively, the reduction process is controlled by diffusion. The reduction potential of Y（Ⅲ） ions is close to the active ions of fluoride melts, but strengthened phase AI3 Y can be formed through electrochemical reduction and alloyed process with active Al（Ⅲ） and Cu（Ⅱ） ions, meanwhile, the Al2 Cu and Al3 Y phases are distributed at the grain boundary of Al matrix.

Cathodic behavior of scandium(Ⅲ) on reactive copper electrodes in LiF-CaF_(2)eutectic molten salt

The electrochemical formation of Sc-Cu alloy was investigated in LiF-CaF_(2) eutectic molten salt employing various electrochemical methods.Cyclic voltammetry and square wave voltammetry indicate that the reduction of scandium(Ⅲ) on the tungsten electrode is a one-step reduction process with three electrons transfer.And underpotential deposition of scandium on the copper electrode occurs owing to the depolarization effect,i.e.,forming Sc-Cu intermetallic compounds.The thermodynamic properties of the Sc-Cu intermetallic compounds ScCu_(4),ScCu_(2),and ScCu in the temperature range of 1153-1223 K were estimated by open-circuit chronopotentiometry.Moreover,the Sc-Cu alloys were prepared by potentiostatic electrolysis and characterized by optical microscope,X-ray diffraction,scanning electron microscopy,and energy dispersive spectroscopy.The results reveal that only Sc-Cu alloy composed of Cu-ScCu_(4) can be synthesized at low cathodic current density and above eutectic temperature.

A garnet-electrolyte based molten Li-I_(2) battery with high performance

Lithium-iodine(Li-I_(2))battery exhibits high potential to match with high-rate property and large energy density.However,problems of the system,such as evident sublimation of iodine elements,dissolution of iodine species in electrolyte,and lithium anode corrosion,prevent the practical use of rechargeable Li-I_(2)batteries.In this work,a molten Li-I_(2)typical cell design which has distinct advantages based on the solid-state garnet electrolyte with the eutectic iodate cathode is firstly developed.The U-shaped ceramic electrolyte tube can separate Li anode from the eutectic iodate cathode,so as to better tackle the above-mentioned inherent challenges for the liquid electrolyte systems.Without self-discharging and lithium anode corrosion,this solid-state battery system demonstrates high safety margin and excellent electrochemical performance.Also,the simple battery structure also indicates the easy assembly process and recycling of electrode materials.With the cathode loading of 593 mg in a single cell,an energy density of~506.7 Wh·kg^(-1)was achieved at 1 C and a long-term cycling life for 2,000 cycles also displays negligible capacity decay.