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With the large-scale application of lithium-ion batteries, the recycling of retired LIBs has been a crucial problem to address. Among the spent LIBs, LiFePO4 (LFP) recycling is urgently needed as it is one of the most extensively utilized cathodes in the sustainable development of LIBs. However, traditional pyro-/hydro-metallurgical recycling methods are normally complicated and uneconomical. Here, we exhibit an efficient and green method with a simple route to regenerate a degraded LiFePO4 cathode, through which the cathode sheets are directly broken down into aluminum foil, high-purity FePO4 and lithium-containing solution by the introduction of hydrogen peroxide as a leaching reagent. The leaching efficiency of Li exceeds 96.3% with scarce Al and Fe, and the regenerated LiFePO4 from recovered FePO4 displays excellent rate capability and long-term cycling stability. This research greatly reduces the processing steps and chemical consumption, which is conducive to the sustainable industrial development of spent lithium-ion batteries. [ABSTRACT FROM AUTHOR]

The ever‐increasing energy density requirements in electric vehicles (EVs) have boosted the development of Ni‐rich layered oxide cathodes for state‐of‐the‐art lithium‐ion batteries. Nevertheless, the commercialization of polycrystalline Ni‐rich cathodes (PCNCs) is hindered by the severe performance degradation and safety concerns that are tightly related to its particle cracking during cycling. Single‐crystalline Ni‐rich cathodes (SCNCs) with eliminated grain boundaries and high mechanical strength have recently attracted extensive attention owing to their superior structural and cycling stability, which present high crack resistance during electrochemical operation. Various articles have focused on the trial‐and‐error synthesis and modifications of SCNCs, as well as the comparison of performances and mechanisms with PCNCs. However, there has been much less effort in systematic analysis and summary to reveal their key challenges, controversies, and the corresponding primary causes. In this review, the advantages and debates in structural and electrochemical properties of SCNCs over PCNCs are summarized to provide fundamental understanding of SCNCs. Then the current practical issues and challenges are comprehensively discussed from the viewpoints of both academia and industry, as well as the proposed modification strategies and underlying mechanisms for SCNCs. The outlook and perspectives are further given to facilitate the commercial applications of SCNCs in high‐performance EVs. [ABSTRACT FROM AUTHOR]

Highlights: The chemical process of local oxidation–partial reduction–deep coupling for stibnite reduction of carbon dots (CDs) is revealed by in-situ high-temperature X-ray diffraction. Sb2S3@xCDs anode delivers high initial coulombic efficiency in lithium ion batteries (85.2%) and sodium ion batteries (82.9%), respectively. C–S bond influenced by oxygen-rich carbon matrix can restrain the conversion of sulfur to sulfite, well confirmed by X-ray photoelectron spectroscopy characterization of solid electrolyte interphase layers helped with density functional theory calculations. CDs-induced Sb–O–C bond is proved to effectively regulate the interfacial electronic structure. The application of Sb2S3 with marvelous theoretical capacity for alkali metal-ion batteries is seriously limited by its poor electrical conductivity and low initial coulombic efficiency (ICE). In this work, natural stibnite modified by carbon dots (Sb2S3@xCDs) is elaborately designed with high ICE. Greatly, chemical processes of local oxidation–partial reduction–deep coupling for stibnite reduction of CDs are clearly demonstrated, confirmed with in situ high-temperature X-ray diffraction. More impressively, the ICE for lithium-ion batteries (LIBs) is enhanced to 85%, through the effect of oxygen-rich carbon matrix on C–S bonds which inhibit the conversion of sulfur to sulfite, well supported by X-ray photoelectron spectroscopy characterization of solid electrolyte interphase layers helped with density functional theory calculations. Not than less, it is found that Sb–O–C bonds existed in the interface effectively promote the electronic conductivity and expedite ion transmission by reducing the bandgap and restraining the slip of the dislocation. As a result, the optimal sample delivers a tremendous reversible capacity of 660 mAh g−1 in LIBs at a high current rate of 5 A g−1. This work provides a new methodology for enhancing the electrochemical energy storage performance of metal sulfides, especially for improving the ICE. [ABSTRACT FROM AUTHOR]

Carbon dots (CDs) are considered as excellent structural regulator for metal oxides (MOs) due to their abundant functional groups, superior dispersibility, and ultrasmall size (<10 nm). Herein, a new approach is proposed to construct porous pomegranate‐like MOs/CDs composite based on the CDs‐induced in situ growth mechanism of ion adsorption–multipoint surface nucleation–crosslinking agglomeration. The proposed methodology is successfully applied to prepare SnO2/CDs, Cu2O/CDs, and Fe2O3/CDs composites, respectively, demonstrating its universality to metal oxides. Taking SnO2/CDs composite as a case study for anode material in lithium‐ion batteries, it exhibits high lithium storage capacity, excellent cycling stability, and a special feature of capacity increase upon cycling. This study provides a new idea for the design of metal oxides materials tuned by CDs and broadens the application of CDs in the field of material synthesis. [ABSTRACT FROM AUTHOR]

The recycling of spent lithium-ion batteries (LIBs) is a crucial issue that has engaged extensive attention worldwide, along with the rapidly increasing usage of lithium-ion batteries. State-of-art recycling approaches, in terms of chemical leaching, have imperfections such as excessive chemical consumption, tedious recycling procedure and aggravated secondary pollution. In this research, a green and closed-loop route for the recycling of spent LiFePO4 involving oxidation leaching is demonstrated. By properly adjusting or controlling the leaching parameters, the leaching efficiency of lithium is up to 97.6% with the introduction of hydrogen peroxide, which is facilitated to achieve the transformed high-purity lithium carbonate and iron phosphate. The oxidation reaction mechanisms are clarified through thermodynamic and kinetic analyses, which identified that the oxidation leaching reaction is co-controlled by the internal diffusion and chemical reaction. Consequently, LiFePO4 cathode materials are regenerated by utilizing the obtained raw materials, as expected, which deliver superior cycling stability with less than 1% of capacity loss after 300 cycles and excellent rate performances. This research embodies the possibility of efficient recycling of LiFePO4 from spent lithium-ion batteries based on the principles of green chemistry that is possibly committed to the sustainability of the lithium-ion battery industry. [ABSTRACT FROM AUTHOR]

Fabrication of Bi/C composites is a common approach to alleviate the severe volume expansion of Bi alloy‐based anodes with a high theoretical capacity of 3800 mAh cm−3 for lithium ion batteries (LIBs). However, the complicated and tedious synthetic routes restrict its large‐scale preparation and practical applications. Herein, a spongiform porous Bi/C composite (marked as Bi@PC) through the carbothermal reduction (CTR) method is constructed. Bi nanodots are in situ confined in a porous carbon substrate activated by the gases produced from the decomposition of the sodium phytate precursor, indicating the feasibility and simplicity of this route. In charge/discharge processes, Bi nanodots embedded in carbon matrix are effective enough to accommodate the strain change and shorten the migration distance. In addition, the porous carbon forms an efficient conductive network for electron shutting. When utilized for lithium storage, a superb capacity of 520 mAh g−1 at 0.2 A g−1 after 100 cycles and a satisfying long cyclic stability of 380 mAh g−1 at 0.5 A g−1 after 500 cycles are achieved. The excellent Li‐storage performance and this handy preparation method jointly make this Bi/C composite a potential anode for LIBs, and could inspire the preparation of other alloy‐type anodes. [ABSTRACT FROM AUTHOR]

Attributed to the high theoretical capacity and abundant reserve, Cu3Mo2O9 has been considered as a potential anode material for lithium‐ion batteries. Nevertheless, the severe capacity fading caused by structure collapse and particle aggregation seriously hinders its practical application. In this work, Cu3Mo2O9 coated with homogeneous polyaniline layer is obtained through oxidative polymerization of aniline on the surface of Cu3Mo2O9. The lithium storage performance is investigated systematically. As a result, a high reversible specific capacity of 800.2 mA h g−1 at a current density of 100 mA g−1 is delivered in Cu3Mo2O9@PANI anode even after 200 cycles, which is much higher than that of pristine Cu3Mo2O9 anode (373.8 mA h g−1). Furthermore, a high capacity of 675 mA h g−1 at a high current density of 1 A g−1 is achieved even after 700 cycles. This result evidences that the introduction of a polyaniline protective layer is an effective way to improve the structural stability of the Cu3Mo2O9 anode and further enhance cycling durability. This strategy is a starting point for the preparation and stabilization of other binary metal oxide composite materials for applications in lithium‐ion batteries. Icing on the cake: Cu3Mo2O9@PANI composites are designed as anode material for lithium‐ion batteries (LIB). The prepared electrode exhibits excellent lithium storage performance. An especially good cyclic stability is found, with a delivered stable reversible capacity of 675 mA h g−1 even after 700 cycles at a high current density of 1 A g−1. [ABSTRACT FROM AUTHOR]

Recently, the carbonization of metal organic frameworks (MOFs) has become an efficient method to prepare metal‐oxide materials on carbon support, which can provide advantages toward conversion‐type reactions of lithium ion batteries as the size and shape of the materials can be tuned by adjusting the MOF ligands. Formic acid is widely used in MOFs with diverse coordination models, which can further regulate morphologies of the carbonized metal oxides. However, less work is reported on the fabrication of metal oxides with formic acid ligands and their application as electrode materials. Herein, utilizing the self‐assembled MOFs [NH2(CH3)2][FeIIIFeII(HCOO)6] with formic acid ligands as the precursor, a carbon decorated Fe3O4 is successfully prepared, consisting of Fe3O4 nanoparticles with diameters of 40–60 nm and the coated carbon that is stemmed from the organic precursor of formic acid. When used as the electrode materials for lithium‐ion batteries, this composite exhibits good rate capability and stabilized reversible capacity of 1041 mAh g−1 after 50 cycles at 100 mA g−1. These superior properties can be attributed to the synergetic effect of the unique nano/micro structure and uniform dispersion of the conductive carbon provided by this new MOF precursor. Enter the (carbon) matrix: carbon decorated Fe3O4 nanoparticles are successfully designed and synthesized using a MOF precursor. The composite material is applied as anodes in lithium‐ion batteries. The electrodes exhibited good rate capability and stable reversible capacity of 1041 mAh g−1 after 50 cycles at a current density of 100 mA g−1. [ABSTRACT FROM AUTHOR]

The ever-increasing demand of lithium-ion batteries (LIBs) caused by the rapid development of various electronics and electric vehicles will be hindered by the limited lithium resource. Thus sodium-ion batteries (SIBs) have been considered as a promising potential alternative for LIBs owing to the abundant sodium resource and similar electrochemical performances. In recent years, significant achievements regarding anode materials which restricted the development of SIBs in the past decades have been attained. Significantly, the sodium storage feasibility of carbon materials with abundant resource, low cost, nontoxicity and high safety has been confirmed, and extensive investigation have demonstrated that the carbonaceous materials can become promising electrode candidates for SIBs. In this review, the recent progress of the sodium storage performances of carbonaceous materials, including graphite, amorphous carbon, heteroatom-doped carbon, and biomass derived carbon, are presented and the related sodium storage mechanism is also summarized. Additionally, the critical issues, challenges and perspectives are provided to further understand the carbonaceous anode materials. [ABSTRACT FROM AUTHOR]

Dark-colored rutile TiO2 nanorods doped by electroconducting Ti3+ have been obtained uniformly with an average diameter of ≈7 nm, and have been first utilized as anodes in lithium-ion batteries. They deliver a high reversible specific capacity of 185.7 mAh g-1 at 0.2 C (33.6 mA g-1) and maintain 92.1 mAh g-1 after 1000 cycles at an extremely high rate 50 C with an outstanding retention of 98.4%. Notably, the coulombic efficiency of Ti3+–TiO2 has been improved by approximately 10% compared with that of pristine rutile TiO2, which can be mainly attributed to its prompt electron transfer because of the introduction of Ti3+. Again the synergetic merits are noticed when the promoted electronic conductivity is combined with a shortened Li+ diffusion length resulting from the ultrafine nanorod structure, giving rise to the remarkable rate capabilities and extraordinary cycling stabilities for applications in fast and durable charge/discharge batteries. It is of great significance to incorporate Ti3+ into rutile TiO2 to exhibit particular electrochemical characteristics triggering an effective way to improve the energy storage properties. [ABSTRACT FROM AUTHOR]

A novel and facile in-situ methodology has been developed to prepare well carbon-coated anatase titanium dioxide (TiO 2 ) nanoparticles. The hydrolysis of tetrabutyl titanate has been effectively controlled in a collosol of N-methyl-2-pyrrolidone dissolved with polyvinylidene fluoride. The as-resulted carbon-dispersed TiO 2 nanoparticles distributed in ranges from 20 to 30 nm in diameter have been obtained with a carbon content of 11.7 wt%. This nanocomposite utilized as anode materials in lithium-ion battery can deliver a high reversible specific capacity of 218 mAh g −1 at the current density of 0.2 C (33.5 mA g −1 ), and still exhibit 100 mAh g −1 at 10 C (1.68 A g −1 ), illustrating notable high-rate performances for the potential application in fast charge/discharge batteries. [ABSTRACT FROM AUTHOR]

Mn 3 O 4 /graphite powder (Mn 3 O 4 /GhP) composite was successfully obtained utilizing an alternating voltage induced electrochemical method. It was found that Mn 3 O 4 particles (∼20 nm) resulted from Mn electrodes were well dispersed on the surface of GhP. The electrochemical performances of Mn 3 O 4 /GhP material as anode for lithium-ion batteries were investigated, demonstrating high specific capacity and excellent cycling stability with a high charge-discharge capacity of 1007.4 mAh g −1 after 50 cycles at a current density of 100 mA g −1 . [ABSTRACT FROM AUTHOR]

Abstract: Sn hollow nanospheres (HNSs) were prepared by galvanic replacement, employing Ni nanospheres (NSs) as templates. The formation process and electrochemical performance of Sn HNS were studied. The Sn HNS resulted in better stability and electrochemical performance when used as an anode material in lithium-ion batteries. The Sn HNS electrode retained a good reversible capacity of 516.1mAhg−1 after 50 cycles at a current density of 100mAhg−1, which was much higher than that of Sn NS (128mAhg−1). TEM images of the Sn HNSs after 50 cycles indicated that the volume expansion outside the spheres had been alleviated, and the aggregation between the active materials had been prevented. [Copyright &y& Elsevier]

Nonoxidative cathodically induced graphene (CIG) here incorporates conductive agents for Li4Ti5O12 (LTO) anode materials. The tailored LTO/CIG composite is fabricated by controlled hydrolysis of tetrabutyl titanate in the presence of nonoxidative defect-free cathodically induced graphene (CIG) and oxalic acid in a mixed solvent of ethanol and water, followed by hydrothermal reaction and a calcination treatment. Due to the introduction of defect-free graphene, the resulting LTO/CIG composite shows an excellent electrical conductivity (1.2 × 10−4 S cm−1) and Li+ diffusion coefficient (1.61 × 10−12 cm2 s−1). As a result, the tuned LTO/CIG composite exhibits outstanding electrochemical performance, including excellent cycling stability (the capacity retention ratios after 500 cycles at 0.5 C is 96.2%) and a remarkable rate capability (162 mAh g−1 at 10C, 126 mAh g−1 at 100 C). A specific energy of 272 Wh kg−1 at power of 136 W kg−1 is observed when cycling against Li-foil. Even during 36 s of charge/discharge, the specific energy of LTO/CIG composite remains at 166 Wh kg−1. [ABSTRACT FROM AUTHOR]

Ni-rich layered transition metal oxide is one of the most promising cathode materials for the next generation lithium-based automotive batteries due to its excellent electrochemical performances. Nevertheless, its further applications are capped by the structural/interfacial instability during the prolonged charging/discharging, leading to severe performance fading and serious safety concerns. Here, we provide a comprehensive review about challenges and solutions to modify Ni-rich layered cathodes specifically for microcrack failure. Firstly, the mechanism of microcrack formation and evolution are concluded thoroughly. Secondly, recent advances in stabilizing the structure/interface of Ni-rich cathodes are summarized such as surface coating, cation/anion doping, composition tailoring, morphology engineering and electrolytes optimization. Furthermore, strategies to mitigate the microcrack and then boost the electrochemical performance of Ni-rich cathodes at the chemical & mechanical engineering level are presented. More importantly, outlook and perspectives to facilitate the practical application of Ni-rich layered cathodes toward electrical vehicle application are provided as well. The information compiled herein can promote the understanding of the microcracks of Ni-rich cathode materials, including its fundamental science, characterization method, and strategies for designing crack-free Ni-rich cathode materials. Furthermore, we provide a new idea for material modification, which is perspective strategy from crystallographic, structural mechanics and chemistry under the guidance of "chemical-mechanical" effect. [Display omitted] • The mechanism of microcrack formation and evolution are concluded. • Recent advances in stabilizing the structure/interface of Ni-rich cathodes are summarized. • Strategies to mitigate the microcrack and then boost the electrochemical performance of Ni-rich cathodes are presented. • Main challenges and the future horizons are outlooked. [ABSTRACT FROM AUTHOR]

Potassium‐ion batteries (PIBs) are currently drawing increased attention as a promising alternative to lithium‐ion batteries (LIBs) owing to the abundant resource and low cost of potassium. However, due to the large ionic radius size of K+, electrode material that can stably maintain K+ insertion/deintercalation is still extremely inadequate, especially for anode material with a satisfactory reversible capacity. As an attempt, nitrogen/carbon dual‐doped hierarchical NiS2 is introduced as the electrode material in PIBs for the first time. Considering that the introduction of the carbon layer effectively alleviates the volume expansion of the material itself, further improves the electronic conductivity, and finally accelerates the charge transfer of K+, not surprisingly, NiS2 decorated with the bifunctional carbon (NiS2@C@C) material electrode shows excellent potassium storage performances. When utilized as a PIB anode, it delivers a high reversible capacity of 302.7 mAh g−1 at 50 mA g−1 after 100 cycles. The first coulombic efficiency is 78.6% and rate performance is 151.2 mAh g−1 at 1.6 A g−1 of the NiS2@C@C, which are also notable. Given such remarkable electrochemical properties, this work is expected to provide more possibilities for the reasonable design of advanced electrode materials for metal sulfide potassium ion batteries. [ABSTRACT FROM AUTHOR]

Layered lithium transition‐metal oxides are considered as promising cathodes for new‐generation lithium‐ion batteries due to their high capacity and excellent rate capability. Nevertheless, the approach of preparing precursors is generally restricted to the utilization of wet‐chemical methods. Herein, for the first time, an electrochemical strategy is introduced to prepare Ni1/3Mn1/3Co1/3(OH)2 precursor with the mixing at the atomic level by electrochemically anodized Ni–Mn–Co alloy anode, demonstrating the superiorities of high yield without the process of the extreme alkaline environment and complicated process. Furthermore, the layered LiNi1/3Mn1/3Co1/3O2 cathode is obtained through calcining the mixture of precursors and Li sources under a certain calcined temperature. As anticipated, the initial discharge specific capacities of 183.9 mAh g−1 at 0.1 C with a capacity retention of 79.66% after 120 loops are delivered for LiNi1/3Mn1/3Co1/3O2 cathode with calcining at 930 °C, and it also exhibits superior rate capability with specific capacities of 151.1 and 116.5 mAh g−1 at 1 and 10 C, respectively. Therefore, this innovative approach can be readily extended to prepare other types of lithiated transition metal oxide precursors. [ABSTRACT FROM AUTHOR]

Three-dimensional copper oxide structures composed of single crystal nanosheets have been successfully prepared by a green electrochemical alternating voltage approach. This special structure of copper oxide grown along the [0 1 0] direction can be effective to accommodate the volume expansion during charge–discharge cycles. The obtained product as anode materials in lithium-ion batteries displays outstanding electrochemical performances with a high reversible capacity of 635.2 mA h g −1 after 50 cycles at 100 mA g −1 close to the theoretical capacity of copper oxide (674 mA h g −1 ). [ABSTRACT FROM AUTHOR]

• H 2 NNS is effective for regeneration of lithium-ion electrode materials. • The leaching condition for simultaneous recovery of valuable metals are optimized. • Electrode materials with microstructure show excellent electrochemical properties. • The principle is potential for recycle of spent battery materials. The resource exhaustion and environmental assessment driven by sustainable development make recycle of spent LIBs urgent to be achieved. However, the conventional recycling processes are quite complicated in terms of the tedious steps and secondary contamination. In this paper, hydrosoluble naphthalenedisulfonic acid is firstly proposed to selectively extract valuable metals (Co and Li) for the regeneration of battery materials. Lithium is selectively recovered as lithium enriched solution with a high yield of 99%, while 96.6% cobalt remains in a complex-precipitate benefited from the high acidity and coordination role of naphthalenedisulfonic acid. The leaching of Li fits well with the logarithmic rate law model with an activation energy of 32.42 kJ/mol. Additionally, the regenerated lithium-ion battery active materials (Co 3 O 4 anode and LiCoO 2 cathode) prepared from the cobalt complex-precipitate and lithium-enriched solution exhibit excellent discharged-charged performances and rate capability. This feasible strategy assisted by multifunctional naphthalenedisulfonic acid may offer an alternative option for the simultaneous recovery of Li and Co and the rational resource utilization of spent lithium-ion batteries. [ABSTRACT FROM AUTHOR]

The transformation of energy structure is deemed as a paramount strategy in accomplishing the ambition of carbon neutrality. Lithium-ion batteries (LIBs), as one of the most exceptional energy storage and conversion devices available, play a pivotal role in this energy revolution. However, due to the extensive production and limited lifespan of LIBs, the retirements of LIBs are set to boom in the coming years. The proper and timely recycling of these batteries are of paramount importance, from both environmental and economic perspectives. Direct cathode regeneration technology is the most promising solution for the treatment of these waste cathodes, as it enables the healing of spent cathodes with minimal energy and chemical consumption, without compromising the original structure of the cathode. Herein, we analyzed the degraded mechanisms of spent LIBs and found that relithiation and defect reparation are crucial steps for the regeneration of spent cathode materials. Various direct regeneration methods previously reported have been summarized, and their respective advantages and limitations as well as technical challenges when implemented into practical industrial applications are discussed. In addition, possible solutions to these problems are proposed, which guide the future direction for the sustainable development of the battery recycling industry. • The degraded mechanisms of spent lithium-ion batteries are summarized. • Current status on direct regeneration of spent cathodes is presented. • The advantages and limitations of direct regeneration approaches are identified. • The future directions of direct regeneration strategies were proposed. [ABSTRACT FROM AUTHOR]

The booming development of the lithium-ion battery market has aroused the transformation of people's consumption and life style. As a significant branch of lithium-ion batteries, LiFePO 4 (LFP)-type batteries has been widely employed in electric vehicles and energy storage devices due to its high safety and decent charge-discharge stability. Nevertheless, the resulted massive scrap of LFP batteries will greatly pose environmental threats and waste of resources if appropriate technical means are not adopted. The advanced recycling methods of spent LFP cathode have long been constantly explored in recent years but have not been systematically discussed. Hence, this review comprehensively summarizes the recovery technologies of spent LiFePO 4 cathode in the current status, including traditional pyro-/hydro-metallurgical processes, direct regeneration and other innovative methods, etc. Furthermore, the pretreatment process is also covered to promote all-sided understanding of the development of LFP cathode recovery approaches. Based on the systematic analysis of spent LFP cathode recycling, the future outlook of efficient recycling methods is proposed to promote the sustainable development of spent lithium-ion batteries. Schematic illustration of strategies and characteristics towards spent LFP cathode recycling. [Display omitted] • A comprehensive summary and prospect of spent LFP cathode recycling. • Pretreatment is introduced to ensure deep understanding of recycling implication. • Mainstream recycling technologies of spent LFP battery are reviewed. • Up-to-date novel recycling methods for spent LFP cathode are summarized. • Future challenges and perspectives are proposed to promote efficient recycling. [ABSTRACT FROM AUTHOR]

Abstract Structural fabrication and modification are the effective approaches to regulate the electrochemical performances of anatase TiO 2. Herein, the template-annealing-etching processes are carried out to synthesize inverse opal TiO 2 with N-doped carbon layer and oxygen vacancies surface as an anode material for advanced lithium ion batteries and sodium ion batteries. These structural features not only shorten the diffusion paths and enhance the electronic conductivity, but also induce the dominant pseudocapacitive contribution. As a result, the as-prepared electrode exhibits the excellent Li+/Na+ storage performances, including a high capacity retention (462 mAh g−1 after 300 cycles at 0.5 A g−1) and a fast cycling capability (180 mAh g−1 after 3500 cycles under 10 A g−1) for lithium storage; a reversible capacity of 140 mAh g−1 after 400 cycles under 1 A g−1 for sodium storage. Revealed by cyclic voltammetry, the pseudocapacitive contribution is as high as 74.49% and 73.38% at 1 mV s−1 for lithium ion batteries and sodium ion batteries, respectively. This work may promise a general approach to synthesize metal oxides anode materials for advanced energy storage devices. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Pure lithium carbonate was recycled from spent graphite. • Graphite was regenerated by a two-stage calcination and acid leaching. • Regenerated graphite has impressive electrochemical performances. Abstract Recycling lithium and graphite from spent lithium-ion battery plays a significant role in mitigation of lithium resources shortage, comprehensive utilization of spent anode graphite and environmental protection. In this study, spent graphite was firstly collected by a two-stage calcination. Secondly, under the optimal conditions of 1.5 M HCI, 60 min and solid-liquid ratio (S/L) of 100 g·L−1, the collected graphite suffers simple acid leaching to make almost 100% lithium, copper and aluminum in it into leach liquor. Thirdly, 99.9% aluminum and 99.9% copper were removed from leach liquor by adjusting pH first to 7 and then to 9, and thenthe lithium was recovered by adding sodium carbonate in leach liquor to form lithium carbonate with high purity (>99%). The regenerated graphite is found to have high initial specific capacity at the rate of 37.2 mA·g−1 (591 mAh·g−1), 74.4 mA·g−1 (510 mAh·g−1) and 186 mA·g−1 (335 mAh·g−1), and with the high retention ratio of 97.9% after 100 cycles, it also displays excellent cycle performance at high rate of 372 mA·g−1. By this process, copper and lithium can be recovered and graphite can be regenerated, serving as a sustainable approach for the comprehensive utilization of anode material from spent lithium-ion battery. [ABSTRACT FROM AUTHOR]

By reason of rich sodium resources, sodium-ion batteries have excited enormous consideration for adhibition in the developing energy-storage stations. And not surprisingly, the exploration of cost-effective anode materials for SIBs have been a conspicuous topic. Herein, iron trioxide embedded in the nitrogen-doped carbon matrix with strong oxygen-bridge bonds is synthesized by using the iron based metal organic framework as template. The obtained composite delivers excellent electrochemical properties, such as specific capacity of 473.7 mAh g −1 at the current density of 100 mA g −1 after 100 cycles. Besides, the reversible capacity still remains at 155.3 mAh g −1 at the high density of 4000 mA g −1 . This remarkable sodium-ion storage capability could be attributed to the incorporation of nitrogen atoms into carbon matrix and the strong chemical bonds between iron trioxide and carbon matrix, which can restrain electrode pulverization and also retain an interparticle connection even after long cycling that could offer a good electronic conductive pathway. This engineer strategy for preparing iron trioxide possess strong interfacial interaction with nitrogen-doped carbon matrix can be applied to other metal phosphides and metal oxide materials. [ABSTRACT FROM AUTHOR]

[Display omitted] • C 6 H 12 O 6 as a reagent resulted in LiCoO 2 reduction at low temperature (<550 °C). • LiCoO 2 reduction mechanisms have been determined by thermodynamic calculations. • 97% of Li can be selective leached out by using water as the only leaching reagent. • The recovered Li 2 CO 3 and Co 3 O 4 could be directly used for cathode regeneration. • The proposed closed-loop process mitigates energy consumption, pollution and costs. Due to the mounting pressure to mitigate environmental pollution and guarantee the sustainability of the battery metals, the recycling of spent lithium-ion batteries (LIBs) has become a crucial issue in recent years. Numerous studies have focused on utilizing high temperatures or strong acid/alkali to reduce the spent active cathode material to a low valence state, which exacerbates recycling and post-treatment costs. Herein, a low-temperature roasting process followed by a water leaching strategy is developed to recycle and regenerate LiCoO 2 cathode material from spent LiCoO 2 batteries. The spent LiCoO 2 is roasted with glucose (C 6 H 12 O 6) as a reagent to attain reduction of the cathode material into water-soluble Li salt (Li 2 O and Li 2 CO 3) and water-insoluble (Co and CoO). The proposed method utilizes moderate roasting temperature and water as the only leaching reagent, which effectively reduces energy and chemical consumption. Li and Co recovery rates are 97 % and 99 %, respectively, under the optimal conditions of 1 h roasting at 550 °C followed by 30 min water leaching using a solid–liquid ratio of 50 g/L. The recovered Li-rich solution and Co-rich residue can be easily converted to Li 2 CO 3 and Co 3 O 4 , respectively, which are the precursors for regenerating the LiCoO 2 cathode material. The regenerated LiCoO 2 exhibits superior cycling stability with 87 % capacity retention after 800 cycles at 4.4 V. This developed closed-loop recycling process has lower recycling costs, is eco-friendly and efficient, and thus could potentially promote the sustainable long-run development of the LIBs industry. [ABSTRACT FROM AUTHOR]

Cathodic corrosion, a green electrochemical method, has been employed to obtain Sb nanomaterials utilized as anode material for lithium-ion batteries and sodium-ion batteries. Interestingly, two different corrosion mechanisms are found, coming from the impact of electrolyte, resulting in the formation of hexagonal and amorphous Sb in aqueous and organic solution, respectively. With the help of water-soluble carboxymethyl cellulose binder and the electrolyte additive fluoroethylene carbonate, both hexagonal and amorphous Sb electrodes exhibit good cycling stability when utilized as anode materials for lithium-ion batteries and sodium-ion batteries. Additionally, both the hexagonal and amorphous Sb electrodes show very good rate capability in lithium-ion batteries. Even at high current density (2000 mA g −1 ), the hexagonal and amorphous Sb give reversible capacities of 422 and 379 mA h g −1 , respectively. Surprisingly, when used as anode materials for sodium-ion batteries, the hexagonal Sb electrode exhibits a good rate performance of 632, 625, 569, 515 and 426 mA h g −1 at a current density of 100, 200, 500, 1000, and 2000 mA g −1 , respectively. However, limited rate performance is observed from the amorphous Sb electrode in case of sodium-ion battery due to the large impedance. [ABSTRACT FROM AUTHOR]

NASICON Na 3 V 2 (PO 4 ) 3 and Na 3 V 2 (PO 4 ) 2 F 3 have restarted to be investigated electrochemically as promising cathode materials for sodium-ion batteries. Fluorine insertion by replacing partial phosphate groups in Na 3 V 2 (PO 4 ) 3 allows for new family of host lattice structure, Na 3 V 2 (PO 4 ) 2 F 3 . Greatly, fluorine is capable to participate in structural construction to change the ions configuration which involves ions occupation, the species and amount of diverse Na sites, leading to distinct modalities for ions extraction. The inductive effects of (PO 4 ) 3− polyanion by changing electronic cloud density upon compositional atoms could be enhanced under the effects of the formed F-V bond due to its strong ionicity, which can moderate the energetics of the transition metal redox couple to generate relatively high operating potentials. The substitution of fluorine for negative-charge polyanion or anion could be effective to improve the electrochemical properties, particularly for the purpose to increase performed voltages by changing atomic environments. [ABSTRACT FROM AUTHOR]

• Role of bead milling and recrystallization on the improvement of cycling stability was investigated. • The phase transition of Fe-doped ZnS from doping Fe to amorphous FeS was characterized. • The first-principles calculation to investigate Fe-doped ZnS and S -doped carbon was performed. The use of ZnS as anode materials in lithium-ion batteries (LIBs) has exhibited particular advantages of high theoretical capacity (962.3 mAh•g−1) and low discharge platform. Compared to chemosynthetic ZnS, natural marmatite (Fe-doped ZnS) can be regarded as a promising anode material with higher conductivity and lower cost. In this work, Fe-doped ZnS composites-1/2/3 (FZC-1/2/3) were synthesized by three methods: bead-milling, bead-milling with Super P , and solid-phase recrystallization (SPR) after bead-milling with Super P , respectively. FZC-3 exhibited high initial discharge and charge capacities of 1031.2 and 825.6 mAh g−1, respectively. Even after 200 cycles, it retained a charge capacity of 672.0 mAh g−1 at 0.2 A g−1, with a coulombic efficiency (CE) of 99.6%. Even at high specific currents of 2.0 and 10.0 A g−1, the maintained discharge capacities of 555.1 and 183.2 mAh g−1 after 1000 cycles, respectively, and the CE was almost 100%. In addition, phase transition of Fe and aggregation structure were characterized to explore the improvement of cycling stability. Furthermore, the first-principles calculation was performed to investigate Fe-doped ZnS and S -doped carbon. This work will provide a simple and practical method to produce marmatite-based anodes for LIBs. [Display omitted] [ABSTRACT FROM AUTHOR]

An electrochemical collision method focusing on individual particles is applied to investigate the LiNi 0.8 Mn 0.1 Co 0.1 O 2 for direct and accurate information about the ions migration process. For the first time, two types of unique current signals including trapezoid-like signals and wider-wave signals are observed with the increase of particle sizes, except for the acquainted spike-like signals with a sharp rise and a slow decay. The trapezoid-like signals started with a slow rise following by a steady platform and a slow decay, revealing an out-of-sync reaction at the beginning and a subsequent interface traversing and internal ion diffusion jointly controlled ions migration process in the particle. The wider-wave signals with a slower rise and a much slower decay are acquired from particles with the largest size, showing the slowest kinetics during the whole reaction process in the particle. [Display omitted] • The de-insertion process of Li+ in single LiNi 0.8 Mn 0.1 Co 0.1 O 2 is studied. • Ion diffusion process changes with particle size. • Current signals with specific feature is found for the first time. • Ion diffusion inside the particle/cross the interface determine the rate capability. [ABSTRACT FROM AUTHOR]

• N-rich carbon nanotubes with long aspect ratio are constructed by a simple template method. • The nitrogen content in the carbon nanotubes is up to 15.7%. • Excellent cycle durability and rate capability are obtained in sodium/lithium ion batteries. • Quantitative kinetic analysis reveals the dominated capacitive contribution. An effective design of carbon materials with appropriate nanoarchitecture and optimized physicochemical property is critically demanded for superb lithium/sodium storage capacities. N-rich (up to 15.7%) hollow carbon nanotubes (NCNT) with long aspect ratio are well developed via a template method by exploring polypyrrole as the high nitrogen-containing carbon precursor. Owing to the hollow structure with large cavity and long aspect ratio, the NCNT exhibits Li+/Na+ storage capability with favorable volume buffer and rapid ion and electron transfer at high rate, resulting in long-term cycling and high-rate property. Meanwhile, the high N content creates abundant active sites and extrinsic defects, facilitating the improved specific capacity and rate performance. Impressively, our NCNT-600 electrode displays a favorable reversible capacity of 132 mAh g−1 after 5000 cycles at 4000 mA g−1 for SIBs and 170 mAh g−1 after 2000 cycles at the same current for LIBs. Further quantitative kinetic analysis reveals the dominated capacitive contribution of Li+/Na+ storage in NCNT, which is attributed to the porous hollow nanotubes and N-rich carbon with volume strain mitigation and enhanced electronic/ionic transfer capability. Given the cost-effectiveness and material sustainability, our work will shed light on the further design of other carbon-based materials for advanced energy storage devices. [ABSTRACT FROM AUTHOR]