Selective lithium recovery and regeneration of ternary cathode from spent lithium-ion batteries:Mixed HCl-H_(2)SO_(4) leaching-spray pyrolysis approach

The recycling of spent lithium-ion batteries(LIBs) is crucial for environmental protection and resource sustainability.However,the economic recovery of spent LIBs remains challenging due to low Li recovery efficiency and the need for multiple separation operations.Here,we propose a process involving mixed HCl-H_(2)SO_(4) leaching-spray pyrolysis for recycling spent ternary LIBs,achieving both selective Li recovery and the preparation of a ternary oxide precursor.Specifically,the process transforms spent ternary cathode(LiNi_(x)Co_yMn_(2)O_(2),NCM) powder into Li_(2)SO_(4) solution and ternary oxide,which can be directly used for synthesizing battery-grade Li_(2)CO_(3) and NCM cathode,respectively.Notably,SO_(4)^(2-) selectively precipitates with Li^(+) to form thermostable Li_(2)SO_(4) during the spray pyrolysis,which substantially improves the Li recovery efficiency by inhibiting Li evaporation and intercalation.Besides,SO_(2) emissions are avoided by controlling the molar ratio of Li^(+)/SO_(4)^(2-)(≥2:1),The mechanism of the preferential formation of Li_(2)SO_(4) is interpreted from its reverse solubility variation with temperature.During the recycling of spent NCM811,92% of Li is selectively recovered,and the regenerated NCM811 exhibits excellent cycling stability with a capacity retention of 81.7% after 300 cycles at 1 C.This work offers a simple and robust process for the recycling of spent NCM cathodes.

Construction of truncated-octahedral LiMn2O4 for battery-like electrochemical lithium recovery from brine

The extraction of lithium from salt lakes or seawater has attracted worldwide attention because of the explosive growth of global demand for lithium products. The LiMn_(2)O_(4)-based electrochemical lithium recovery system is one of the strongest candidates for commercial application due to its high inserted capacity and low energy consumption. However, the surface orientation of LiMn_(2)O_(4)that facilitates Li diffusion happens to be prone to manganese dissolution making it a great challenge to obtain high lithium inserted capacity and long life simultaneously. Herein, we address this problem by designing a truncated octahedral LiMn_(2)O_(4)(Tr-oh LMO) in which the dominant(111) facets minimize Mn dissolution while a small portion of(100) facets facilitate the Li diffusion. Thus, this Tr-oh LMO-based electrochemical lithium recovery system shows excellent Li recovery performance with high inserted capacity(20.25 mg g^(-1)per cycle) in simulated brine. In addition, the dissolution rate of manganese per 30 cycles is only 0.44% and the capacity maintained 85% of the initial after 30 cycles. These promising findings accelerate the practical application of LiMn_(2)O_(4)in electrochemical lithium recovery.

Aqueous electrochemical delithiation of cathode materials as a strategy to selectively recover lithium from waste lithium-ion batteries

Lithium recovery from end-of-life Li-ion batteries(LIBs)through pyro-and hydrometallurgical recycling processes involves several refining stages,with high consumption of reagents and energy.A competitive technological alternative is the electrochemical oxidation of the cathode materials,whereby lithium can be deintercalated and transferred to an electrolyte solution without the aid of chemical extracting compounds.This article investigates the potential to selectively recover Li from LIB cathode materials by direct electrochemical extraction in aqueous solutions.The process allowed to recovering up to 98%of Li from high-purity commercial cathode materials(LiMn_(2)O_(4),LiCoO_(2),and Li Ni_(1/3)Mn_(1/3)Co_(1/3)O_(2))with a faradaic efficiency of 98%and negligible co-extraction of Co,Ni,and Mn.The process was then applied to recover Li from the real waste LIBs black mass obtained by the physical treatment of electric vehicle battery packs.This black mass contained graphite,conductive carbon,and metal impurities from current collectors and steel cases,which significantly influenced the evolution and performances of Li electrochemical extraction.Particularly,due to concomitant oxidation of impurities,lithium extraction yields and faradaic efficiencies were lower than those obtained with high-purity cathode materials.Copper oxidation was found to occur within the voltage range investigated,but it could not quantitatively explain the reduced Li extraction performances.In fact,a detailed investigation revealed that above 1.3 V vs.Ag/Ag Cl,conductive carbon can be oxidized,contributing to the decreased Li extraction.Based on the reported experimental results,guidelines were provided that quantitatively enable the extraction of Li from the black mass,while preventing the simultaneous oxidation of impurities and,consequently,reducing the energy consumption of the proposed Li recovery method.

Recovery of lithium using H_(4)Mn_(3.5)Ti_(1.5)O_(12)/reduced graphene oxide/polyacrylamide composite hydrogel from brine by Ads-ESIX process

Powdery Li^(+)-imprinted manganese oxides adsorbent was widely used to the recovery of Li^(+),but there are some difficulties,such as poor stability in acid solution,inconvenience of operation and separation.In this work,a useful hydrogel composite based H_(4)Mn_(3.5)Ti_(1.5)O_(12)/reduced graphene oxide/polyacrylamide(HMTO-rGO/PAM)was fabricated by thermal initiation method with promising stable,conductive and selective properties.The resulting materials were characterized by field emission scanning electron microscope,infrared absorption spectrum,X-ray diffraction,X-ray photoelectron spectroscopy and electrochemical techniques.The recovery of Li^(+)was investigated using HMTO-rGO/PAM from brine by a separated two-stage sorption statically and electrically switched ion exchange desorption process.The adsorption capacity of 51.5 mg·g^(-1)could be achieved with an initial Li^(+)concentration of 200 mg·L^(-1)in pH 10,at 45℃ for 12 h.Li^(+)ions could be quickly desorbed by cyclic voltammetry(CV)in pH 3,0.1 mol·L^(-1)HCl/NH;Cl accompanying the exchange of Li^(+)and H+(NH;)and the transfer of LMTO-rGO/PAM to HMTO-rGO/PAM.

Performance comparison of lithium fractionation from magnesium via continuous selective nanofiltration/electrodialysis

Although selective nanofiltration(SNF)and selective electrodialysis(SED)have been widely adopted in the field of Mg^(2+)/Li^(+)separation,their differences have not been illustrated systematically.In this study,for the first time,SNF and SED processes in continuous mode were studied for Li+fractionation from the same brine with high Mg/Li ratios and their differences were discussed in detail.For a fair analysis of the two processes,typical factors were optimized.Specifically,the optimal operating pressure and feed flow rate for SNF were 2.4 MPa and 140 L·h^(-1),respectively,while the optimal cell-pair voltage and replenishment flow rate for SED were 1.0 V and 14 L·h^(-1),respectively.Although the Li^(+)fractionation capacity of the two processes were similar,the selectivity coefficient of SNF was 24.7% higher than that of SED and,thus,the Mg/Li ratio in purified stream of the former was 19.0% lower than that of the latter.Due to higher ion driving force,SED had clear advantages in recovery ratio and concentration effects.Meanwhile,the specific energy consumption of SED was 20.1% lower than that of SNF.This study provided a better understanding and guidance for the application and improvement of the two technologies.

Crystallization of battery-grade lithium carbonate with high recovery rate via solid-liquid reaction

Lithium carbonate(Li_(2)CO_(3))stands as a pivotal raw material within the lithium-ion battery industry.Hereby,we propose a solid-liquid reaction crystallization method,employing powdered sodium carbonate instead of its solution,which minimizes the water introduction and markedly elevates one-step lithium recovery rate.Through kinetic calculations,the Li_(2)CO_(3)solid-liquid reaction crystallization process conforms by the Avrami equation rather than shrinking core model,which means the dissolution rate of Na_(2)CO_(3)is the most important factor affecting the reaction process.The effects of reaction conditions such as temperature and stirring speed on the Li_(2)CO_(3)precipitation behavior were evaluated.The results indicated that temperature is a most essential parameter than other reaction conditions or stirring speed.The exceptional 93%recovery of Li_(2)CO_(3)at 90℃with a remarkable purity of 99.5%was achieved by using 1.2 M ratio of Na_(2)CO_(3)/Li_(2)SO_(4).This method provides a new idea for the efficient preparation of battery-grade Li_(2)CO_(3).

Lithium and manganese extraction from manganese-rich slag originated from pyrometallurgy of spent lithium-ion battery

Mn and Li were selectively extracted from the manganese-rich slag by sulfation roasting−water leaching.The extraction mechanisms of Mn and Li were investigated by means of XRD,TG−DSC,and SEM−EDS.73.71%Mn and 73.28%Li were leached under optimal experimental conditions:acid concentration of 82 wt.%,acid-to-slag mass ratio of 1.5:1,roasting temperature of 800°C,and roasting time of 2 h.During the roasting process,the manganese-rich slag first reacted with concentrated sulfuric acid,producing MnSO_(4),MnSO_(4)·H_(2)O,Li_(2)Mg(SO_(4))_(2),Al_(2)(SO_(4))_(3),and H_(4)SiO_(4).With the roasting temperature increasing,H_(4)SiO_(4) and Al_(2)(SO_(4))_(3) decomposed successively,resulting in generation of mullite and spinel.The mullite formation aided in decreasing the leaching efficiencies of Al and Si,while increasing the Li leaching efficiency.The formation of spinel,however,decreased the leaching efficiencies of Mn and Li.

Extraction of lithium from the simulated pyrometallurgical slag of spent lithium-ion batteries by binary eutectic molten carbonates

The effective and low-temperature extraction of lithium from the pyrometallurgical slag of spent lithium-ion batteries(LIBs)remains a great challenge.Herein,potassium carbonate/sodium carbonate(K_(2)CO_(3)/Na_(2)CO_(3)),which could form a eutectic molten salt system at 720℃,was used as a roasting agent to extract lithium from pyrometallurgical slag.Lithium was successfully extracted from the slag by K_(2)CO_(3)/Na_(2)CO_(3) roasting followed by water leaching.Theoretical calculation results indicate that the lengths of Li-O bonds increase after K^(+)/Na^(+)adsorption,resulting in the easy release of Li^(+)from the LiAlSi_(2)O_(6) lattice after roasting with K_(2)CO_(3)/Na_(2)CO_(3).Thermogravimetry-differential scanning calorimetry results indicate that the eutectic phenomenon of K_(2)CO_(3) and Na_(2)CO_(3) could be observed at 720℃ and that the reaction of the slag and eutectic molten salts occurs at temperatures above 720℃.X-ray diffraction results suggest that Li^(+)in the slag is exchanged by K^(+)in K_(2)CO_(3) with the concurrent formation of KAlSiO_(4),while Na_(2)CO_(3) mainly functions as a fluxing agent.The lithium extraction efficiency can reach 93.87%under the optimal conditions of a roasting temperature of 740℃,roasting time of 30 min,leaching temperature of 50℃,leaching time of 40 min,and water/roasted sample mass ratio of 10:1.This work provides a new system for extracting lithium from the pyrometallurgical slag of spent LIBs.

Negatively charged organic–inorganic hybrid silica nanofiltration membranes for lithium extraction

Effective extraction of lithium from high Mg2+/Li+ratio brine lakes is of great challenge.In this work,organic–inorganic hybrid silica nanofiltration(NF)membranes were prepared by dip-coating a 1,2-bis(triethoxysilyl)ethane(BTESE)-derived separation layer on tubular TiO2 support,for efficient separation of LiC l and MgCl2 salt solutions.We found that the membrane calcinated at 400°C(M1–400)could exhibit a narrow pore size distribution(0.63–1.66 nm)owing to the dehydroxylation and the thermal degradation of the organic bridge groups.All as-prepared membranes exhibited higher rejections to LiCl than to MgCl2,which was attributed to the negative charge of the membrane surfaces.The rejection for LiCl and MgCl2 followed the order:LiCl N MgCl2,revealing that Donnan exclusion effect dominated the salt rejection mechanism.In addition,the triplecoated membrane calcined at 400°C(M3–400)exhibited a permeability of about 9.5 L·m-2·h-1·bar-1 for LiCl or MgCl2 solutions,with rejections of 74.7%and 20.3%to LiCl and MgCl2,respectively,under the transmembrane pressure at 6 bar.Compared with the previously reported performance of NF membranes for Mg2+/Li+separation,the overall performance of M3–400 is highly competitive.Therefore,this work may provide new insight into designing robust silica-based ceramic NF membranes with negative charge for efficient lithium extraction from salt lakes.

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.

Highly selective and green recovery of lithium ions from lithium iron phosphate powders with ozone

Since lithium iron phosphate cathode material does not contain high-value metals other than lithium,it is therefore necessary to strike a balance between recovery efficiency and economic benefits in the recycling of waste lithium iron phosphate cathode materials.Here,we describe a selective recovery process that can achieve economically efficient recovery and an acceptable lithium leaching yield.Adjusting the acid concentration and amount of oxidant enables selective recovery of lithium ions.Iron is retained in the leaching residue as iron phosphate,which is easy to recycle.The effects of factors such as acid concentration,acid dosage,amount of oxidant,and reaction temperature on the leaching of lithium and iron are comprehensively explored,and the mechanism of selective leaching is clarified.This process greatly reduces the cost of processing equipment and chemicals.This increases the potential industrial use of this process and enables the green and efficient recycling of waste lithium iron phosphate cathode materials in the future.

Investigation of Mg^2＋/Li^＋ Separation by Nanofiltration

The Mg2+/Li+/Cl solutions were filtrated with a commercially available DK nanofiltration membrane to investigate the possibility to enrich the lithium component.The investigation was significant as such an approach might be a competing substitute for the present lithium purification industry and the environmental protection purpose.The Donnan steric pore model(DSPM) was implemented for the prediction.The separation of Mg2+/Li+was mainly affected by the working pressure(or the permeation flux) and a limiting separation factor was found around 0.31.The effective membrane charge density was evaluated and its dependence on the permeation flux as well as the ion pattern was discussed.For predicting an actual separation of electrolytes,the experimental investigation seems necessary for the reliability and efficiency.

Enhanced leaching of metals from spent lithium-ion batteries by catalytic carbothermic reduction

Spent Li-ion battery(LIB)recycling has become a challenge with the rapidly developing electric vehicle(EV)industry.To address the problems of high cost and low recovery of Li in the recycling of spent LIBs using traditional hydrometallurgical processes,we developed an alkali metal catalytic carbothermic reduction method to recover spent LiNi_(x)Co_(y)Mn_(z)O_(2)(NCM).Using alkali metal catalysts,such as NaOH,significantly reduced the temperature required for carbothermic NCM material reduction and realized targeted control of the phase of the reduction product,where Li was first separated by prior water leaching,followed by Ni,Co,and Mn recycling by acid leaching.The optimized carbothermic reduction conditions were a reaction time of 3 h,temperature of 550℃,NaOH dosage of 15 wt%,and graphite dosage of 15 wt%.The Li leaching efficiency reached 78.5 wt%during water leaching.And during acid leaching,the Ni,Co and Mn leaching efficiencies were 99.8 wt%,99.7 wt%,and 99.5wt%,respectively.This study provides strong technical support for the development of LIB industry.