Direct Regeneration of Spent Lithium-Ion Battery Cathodes:From Theoretical Study to Production Practice

Direct regeneration method has been widely concerned by researchers in the field of battery recycling because of its advantages of in situ regeneration,short process and less pollutant emission.In this review,we firstly analyze the primary causes for the failure of three representative battery cathodes(lithium iron phosphate,layered lithium transition metal oxide and lithium cobalt oxide),targeting at illustrating their underlying regeneration mecha-nism and applicability.Efficient stripping of material from the collector to obtain pure cathode material has become a first challenge in recycling,for which we report several pretreatment methods currently available for subsequent regeneration processes.We review and discuss emphatically the research progress of five direct regeneration methods,including solid-state sintering,hydrothermal,eutectic molten salt,electrochemical and chemical lithiation methods.Finally,the application of direct regeneration technology in production practice is introduced,the problems exposed at the early stage of the industrialization of direct regeneration technol-ogy are revealed,and the prospect of future large-scale commercial production is proposed.It is hoped that this review will give readers a comprehensive and basic understanding of direct regeneration methods for used lithium-ion batteries and promote the industrial application of direct regeneration technology.

Development of sustainable and efficient recycling technology for spent Li-ion batteries: Traditional and transformation go hand in hand

Clean and efficient recycling of spent lithium-ion batteries(LIBs)has become an urgent need to promote sustainable and rapid development of human society.Therefore,we provide a critical and comprehensive overview of the various technologies for recycling spent LIBs,starting with lithium-ion power batteries.Recent research on raw material collection,metallurgical recovery,separation and purification is highlighted,particularly in terms of all aspects of economic efficiency,energy consumption,technology transformation and policy management.Mechanisms and pathways for transformative full-component recovery of spent LIBs are explored,revealing a clean and efficient closed-loop recovery mechanism.Optimization methods are proposed for future recycling technologies,with a focus on how future research directions can be industrialized.Ultimately,based on life-cycle assessment,the challenges of future recycling are revealed from the LIBs supply chain and stability of the supply chain of the new energy battery industry to provide an outlook on clean and efficient short process recycling technologies.This work is designed to support the sustainable development of the new energy power industry,to help meet the needs of global decarbonization strategies and to respond to the major needs of industrialized recycling.

Pyrometallurgical recycling of spent lithium-ion batteries from conventional roasting to synergistic pyrolysis with organic wastes

The synergistic pyrolysis has been increasingly used for recycling spent lithium-ion batteries(LIBs)and organic wastes(hydrogen and carbon sources),which are in-situ transformed into various reducing agents such as H_(2),CO,and char via carbothermal and/or gas thermal reduction.Compared with the conventional roasting methods,this“killing two birds with one stone”strategy can not only reduce the cost and energy consumption,but also realize the valorization of organic wastes.This paper concluded the research progress in synergistic pyrolysis recycling of spent LIBs and organic wastes.On the one hand,valued metals such as Li,Co,Ni,and Mn can be recovered through the pyrolysis of the cathode materials with inherent organic materials(e.g.,separator,electrolyte)or graphite anode.During the pyrolysis process,the organic materials are decomposed into char and gases(e.g.,CO,H_(2),and CH_(4))as reducing agents,while the cathode material is decomposed and then converted into Li_(2)CO_(3) and low-valent transition metals or their oxides via in-situ thermal reduction.The formed Li_(2)CO_(3) can be easily recovered by the water leaching process,while the formed transition metals or their oxides(e.g.,Co,CoO,Ni,MnO,etc.)can be recovered by the reductant-free acid leaching or magnetic separation process.On the other hand,organic wastes(e.g.,biomass,plastics,etc.)as abundant hydrogen and carbon sources can be converted into gas(e.g.,H_(2),CO,etc.)and char via pyrolysis.The cathode materials are decomposed and subsequently reduced by the pyrolysis gas and char.In addition,the pyrolysis oil and gas can be upgraded by catalytic reforming with the active metals derived from cathode material.Finally,great challenges are proposed to promote this promising technology in the industrial applications.

Recycling Spent LiCoO_(2)Battery as a High-efficient Lithiumdoped Graphitic Carbon Nitride/Co_(3)O_(4)Composite Photocatalyst and Its Synergistic Photocatalytic Mechanism

The ever-increasing quantity of spent lithium-ion batteries(LIBs)is both a potential environmental pollutant and a valuable resource.The spent LIBs recycling mainly aimed at the separation of valuable elements.Some issues still exist in these processes such as high energy consumption and complex separation procedures.This study avoided element separation and proposed a facile approach to transform spent LiCoO_(2) electrode into a lithium(Li)-doped graphitic carbon nitride(g-C_(3)N_(4))/Co_(3)O_(4) composite photocatalyst through one-pot in situ thermal reduction.During the thermal process,melamine served as the reductant for LiCoO_(2) decomposition and the raw material for g-C_(3)N_(4) production.Li was in situ doped in g-C_(3)N_(4) and the generated Co_(3)O_(4) was in situ integrated,forming a Li-doped g-C_(3)N_(4)/Co_(3)O_(4) composite photocatalyst.This special composite exhibited an enhanced photocatalytic performance,and its photocatalytic H2 production and RhB degradation rates were 8.7 and 6.8 times higher than those of g-C_(3)N_(4).The experiments combined with DFT calculation revealed that such enhanced photocatalytic efficiency was ascribed to the synergy effect of Li doping and Co_(3)O_(4) integrating,which extended the visible light absorption(450-900 nm)and facilitated the charge transfer and separation.This study transforms waste into a high-efficient catalyst,realizing high-valued utilization of waste and environmental protection.

Review of preferentially selective lithium extraction from spent lithium batteries: Principle and performance

Lithium,as the lightest and lowest potential metal,is an ideal "battery metal" and the core strategic metal of the new energy industry revolution.Recovering lithium from spent lithium batteries(LIBs)has become one of the significant approaches to obtaining lithium resources.At present,the lithium extraction being generally placed at the last step of the spent LIBs recovery process has puzzles such as high acid consumption,low Li recovery purity and low recovery efficiency.Selective lithium extraction at the first step of the recovery process can effectively solve those puzzles.Since lithium leaching is a non-spontaneous reaction requiring additional energy to achieve,it is found that these methods can be divided into five ways according to the different types of energy driving the reaction occurring:(ⅰ)electric energy driving lithium extraction;(ⅱ) chemical energy driving lithium extraction;(ⅲ) mechanical energy driving lithium extraction;(ⅳ) thermal energy driving lithium extraction;(ⅴ) other energy driving lithium extraction.Through the analysis of the principle,reaction process and results of recovering lithium methods can provide a few directions for scholars’ subsequent research.It is necessary to speed up the exploration of the principle of these methods.It is expected that this study could provide a reference for the research on the selective lithium extraction.

Recent advancements in hydrometallurgical recycling technologies of spent lithium-ion battery cathode materials

The rapidly increasing production of lithium-ion batteries(LIBs)and their limited service time increases the number of spent LIBs,eventually causing serious environmental issues and resource wastage.From the perspectives of clean production and the development of the LIB industry,the effective recovery and recycling of spent LIBs require urgent solutions.This study provides an overview of the current hydrometallurgical processes employed in the recycling of spent cathode materials,focusing on the leaching of valuable metals and their postprocessing.In particular,this research reviews the various leaching systems(inorganic acid,organic acid,and ammonia)and the separation of valuable metals,and then,recommendations for subsequent study are offered in an attempt to contribute to the development of highly efficient methods for recycling spent cathode materials.In addition,a range of existing technologies,such as solvent extraction,chemical precipitation,electrochemical deposition,and regeneration,for the postprocessing of leaching solutions are summarized.Finally,the promising technologies,existing challenges and suggestions with respect to the development of effective and environmentally friendly recycling methods for handling spent cathode materials are identified.

Engineering classification recycling of spent lithium-ion batteries through pretreatment:a comprehensive review from laboratory to scale-up application

The lithium-ion batteries(LIBs)have been widely equipped in electric/hybrid electric vehicles(EVs/HEVs)and the portable electronics due to their excellent electrochemical performances.However,a large number of retired LIBs that consist of toxic substances(e.g.,heavy metals,electrolytes)and valuable metals(e.g.,Li,Co)will inevitably flow into the waste stream,and their incineration or landfill treatment will cause severe risks to ecosystem and human beings.The sustainable and efficient treatment or recycling of valuable resources from spent LIBs should be fully recognized for environmental and resource security.As one of the most important processes for spent LIBs recycling,the pretreatment is an indispensable step,which is directly related to the subsequent metal extraction and separation processes.Although considerable progresses have been made regarding the pretreatment technologies,there are few summarized reports concerning critical processes of spent LIBs recycling,especially combination of currently available recycling technologies with industrialized applications during pretreatments.Therefore,comprehensive review of the current prevailing pretreatment technologies in laboratory to existing scale-up applications is quite necessary to reveal cutting-edge development in the field of pretreatment.In this review,the current pretreatment technologies are systematically categorized and introduced,along with critical discussions.This review focused on the various options for pretreatment processes itself,instead of general spent LIBs recycling technologies without the focused topics that have been sophisticatedly reviewed by previous studies.Here,the deactivation,discharge,dismantling,separation,liberation of active material and electrolyte treatment have been summarized with the in-depth discussion of the technology development and current status of each category.Finally,current states of industrial development are also reviewed and discussed for the development of efficient and environmentally friendly recycling technologies for future applications.This review tends to present a focused topic concerning the pretreatment of spent LIBs to potential readers with a comprehensive illustration of the development on both cutting-edge technologies and scale-up applications.

Valuable metals recovery from spent ternary lithium-ion battery:A review

Ternary lithium-ion batteries(LIBs),widely used in new energy vehicles and electronic products,are known for their high en-ergy density,wide operating temperature range,and excellent cycling performance.With the rapid development of the battery industry,the recycling of spent ternary LIBs has become a hot topic because of their economic value and environmental concerns.To date,a con-siderable amount of literature has reported on the recycling of spent ternary LIBs designed to provide an efficient,economical,and envir-onmentally friendly method for battery recycling.This article examines the latest developments in various technologies for recycling spent ternary LIBs in both research and practical production,including pretreatment,pyrometallurgy,hydrometallurgy,pyro-hydrometallurgy,and direct regeneration.Suggestions for addressing challenges based on the benefits and disadvantages of each method are made.Finally,through a comparison of the feasibility and economic benefits of various technologies,the challenges faced during battery recycling are summarized,and future development directions are proposed.

Selective lithium recovery from black powder of spent lithiumion batteries via sulfation reaction:phase conversion and impurities influence

The aim of this study is to present a new understanding for the selective lithium recovery from spent lithium-ion batteries(LIBs)via sulfation roasting.The composition of roasting products and reaction behavior of impurity elements were analyzed through thermodynamic calculations.Then,the effects of sulfuric acid dosage,roasting temperature,roasting time,and impurity elements were assessed on the leaching efficiency of valuable metals.Characterization methods such as X-ray diffraction(XRD),scanning electron microscopy-energy dispersive spectroscopy(SEM-EDS),and X-ray photoelectron spectroscopy(XPS)were employed to analyze the phase transformation mechanism during roasting process.The results indicate that after sulfation roasting(n(H_(2)SO_(4)):n(Li)=0.5,550℃,2 h),94%lithium can be selectively recovered by water leaching and more than 95%Ni,Co,and Mn can be leached through acid leaching without the addition of reduction agent.During the sulfation roasting process,the lithium in LiNi_(x)Mn_(y)Co_zO_(2)is mainly converted to Li_(2)SO_(4),while the Ni,Co and Mn are first transformed to sulfate and then converted into oxide form.In addition,impurity elements such as Al and F will combine with lithium to form LiF and LiAlO_(2),which will reduce the leaching rate of lithium.These results provide a new understanding on the mechanisms of phase conversion during sulfation roasting and reveal the influence of impurity elements for the lithium recovery from spent LIBs.

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.

A unique co-recovery strategy of cathode and anode from spent LiFePO_(4) battery

Along with the explosive growth in the market of new energy electric vehicles,the demand for Li-ion batteries(LIBs)has correspondingly expanded.Given the limited life of LIBs,numbers of spent LIBs are bound to be produced.Because of the severe threats and challenges of spent LIBs to the environment,resources,and global sustainable development,the recycling and reuse of spent LIBs have become urgent.Herein,we propose a novel green and efficient direct recycling method,which realizes the concurrent reuse of LiFePO_(4)(LFP)cathode and graphite anode from spent LFP batteries.By optimizing the proportion of LFP and graphite,a hybrid LFP/graphite(LFPG)cathode was designed for a new type of dualion battery(DIB)that can achieve co-participation in the storage of both anions and cations.The hybrid LFPG cathode combines the excellent stability of LFP and the high conductivity of graphite to exhibit an extraordinary electrochemical performance.The best compound,i.e.,LFP:graphite=3:1,with the highest reversible capacity(~130 mAhg^(-1) at 25 mAg^(-1)),high voltage platform of 4.95 V,and outstanding cycle performance,was achieved.The specific diffusion behavior of Li^(+) and PF_(6)^(-) in the hybrid cathode was studied using electrode kinetic tests,further clarifying the working mechanism of DIBs.This study provides a new strategy toward the large-scale recycling of positive and negative electrodes of spent LIBs and establishes a precedent for designing new hybrid cathode materials for DIBs with superior performance using spent LIBs.

Preparing graphene from anode graphite of spent lithium-ion batteries

With extensive use of lithium ion batteries （LIBs）, amounts of LIBs were discarded, giving rise to growth of resources demand and environmental risk. In view of wide usage of natural graphite and the high content （12%-21%） of anode graphite in spent LIBs, recycling anode graphite from spent LIBs cannot only alleviate the shortage of natural graphite, but also promote the sustainable development of related industries. After calcined at 600°Cfor 1 h to remove organic substances, anode graphite was used to prepare graphene by oxidation-reduction method. Effect of pH and N2H4·H2O amount on reduction of graphite oxide were probed. Structure of graphite, graphite oxide and graphene were characterized by XRD, Raman and FTIR. Graphite oxide could be completely reduced to graphene at pH 11 and 0.25 mL N2H4·H2O. Due to the presence of some oxygen-containing groups and structure defects in anode graphite, concentrated H2SO4 and KMnO4 consumptions were 40% and around 28.6% less than graphene preparation from natural graphite, respectively.

Highly selective metal recovery from spent lithium-ion batteries through stoichiometric hydrogen ion replacement

Spent lithium-ion battery recycling has attracted significant attention because of its importance in regard to the environment and resource importance.Traditional hydrometallurgical methods usually leach all valuable metals and subsequently extract target meals to prepare corresponding materials.However,Li recovery in these processes requires lengthy operational procedures,and the recovery efficiency is low.In this research,we demonstrate a method to selectively recover lithium before the leaching of other elements by introducing a hydrothermal treatment.Approximately 90%of Li is leached from high-Ni layered oxide cathode powders,while consuming a nearly stoichiometric amount of hydrogen ions.With this selective recovery of Li,the transition metals remain as solid residue hydroxides or oxides.Furthermore,the extraction of Li is found to be highly dependent on the content of transition metals in the cathode materials.A high leaching selectivity of Li(>98%)and nearly 95%leaching efficiency of Li can be reached with LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2).In this case,both the energy and material consumption during the proposed Li recovery is significantly decreased compared to traditional methods;furthermore,the proposed method makes full use of H+to leach Li+.This research is expected to provide new understanding for selectively recovering metal from secondary resources.

Template-free preparation of porous Co microfibers from spent lithium-ion batteries as a promising microwave absorber

In order to take full advantage of the secondary resources,in this paper,we reported a template-free process to prepare porous Co microfibers from spent lithiumion batteries(LIBs).First,the waste LiCoO_(2) powders were leached by oxalic acid at a suitable temperature,and rodlike cobalt oxalate powders were obtained.Second,the porous Co microfibers were prepared by using the cobalt oxalate as precursors through a thermal decomposition at420 ℃ under nitrogen atmosphere.The prepared Co microfibers possess diameters of 1-2 μm,and each microfiber consists of small particles with size of100-200 nm.The Co microfibers(25 wt%)/paraffin composite exhibited excellent microwave absorption performance.When the sample thickness is 4.5 mm,the reflection losses reach-36.14 and-38.20 dB at 4.16 and 17.60 GHz,respectively,and the effective bandwidth reaches up to 5.52 GHz.This indicates that the Co microfibers can be used as a promising microwave absorber.Therefore,this paper demonstrates a novel process to make a high value-added product through recycling from the spent lithium-ion batteries.In addition,it is advantageous to eliminate the hazard of spent lithium-ion batteries and electromagnetic radiation to environment and human health.

Direct reuse of oxide scrap from retired lithium-ion batteries:advanced cathode materials for sodium-ion batteries

The direct reuse of retired lithium-ion batteries(LIBs)cathode materials is one of the optimum choices for"waste-to-wealth"by virtue of sustainable and high economic efficiency.Considering the harmfulness of retired LIBs and the serious shortage of lithium resources,in this work,the spent oxide cathode materials after simple treatment are directly applied to the sodium-ion batteries(SIBs)and exhibit promising application possibilities in advanced SIBs.The spent oxide cathode shows an appropriate initial discharge capacity of 109 mAh·g^(-1)and exhibits transition and activation processes at a current density of 25 mA·g^(-1).Further,it demonstrates decent cycle performance and comparatively good electrode kinetics performance(the apparent ion diffusion coefficient at steady state is about 1×10^(-12)cm^(2)·s^(-1)).The"waste-towealth"concept of this work provides an economical and sustainable strategy for directly reusing the retired LIBs and supplies a large amount of raw material for the largescale application of SIBs.