Direct Regeneration Research Articles

Preoxidation and Prilling Combined with Doping Strategy to Build High-Performance Recycling Spent LiFePO4 Materials.

Direct regeneration has gained much attention in LiFePO4 battery recycling due to its simplicity, ecofriendliness, and cost savings. However, the excess carbon residues from binder decomposition, conductive carbon, and coated carbon in spent LiFePO4 impair electrochemical performance of direct regenerated LiFePO4. Herein, we report a preoxidation and prilling collaborative doping strategy to restore spent LiFePO4 by direct regeneration. The excess carbon is effectively removed by preoxidation. At the same time, prilling not only reduces the size of the primary particles and shortens the diffusion distance of Li+ but also improves the tap density of the regenerated materials. Besides, the Li+ transmission of the regenerated LiFePO4 is further improved by Ti4+ doping. Compared with commercial LiFePO4, it has excellent low-temperature performance. The collaborative strategy provides a new insight into regenerating high-performance spent LiFePO4.

Degradation Mechanisms of Electrodes Promotes Direct Regeneration of Spent Li-Ion Batteries: A Review.

The rapid growth of electric vehicle use is expected to cause a significant environmental problem in the next few years due to the large number of spent lithium-ion batteries (LIBs). Recycling spent LIBs will not only alleviate the environmental problems but also address the challenge of limited natural resources shortages. While several hydro- and pyrometallurgical processes are developed for recycling different components of spent batteries, direct regeneration presents clear environmental, and economic advantages. The principle of the direct regeneration approach is restoring the electrochemical performance by healing the defective structure of the spent materials. Thus, the development of direct regeneration technology largely depends on the formation mechanism of defects in spent LIBs. This review systematically details the degradation mechanisms and types of defects found in diverse cathode materials, graphite anodes, and current collectors during the battery's lifecycle. Building on this understanding, principles and methodologies for directly rejuvenating materials within spent LIBs are outlined. Also the main challenges and solutions for the large-scale direct regeneration of spent LIBs are proposed. Furthermore, this review aims to pave the way for the direct regeneration of materials in discarded lithium-ion batteries by offering a theoretical foundation and practical guidance.

Direct and rapid thermal shock for recycling spent graphite in lithium-ion batteries

Due to the rapid increase in the number of spent lithium-ion batteries, there has been a growing interest in the recovery of degraded graphite. In this work, a rapid thermal shock (RTS) strategy is proposed to regenerate spent graphite for use in lithium-ion batteries. The results of structural and morphological characterization demonstrate that the graphite is well regenerated by the RTS process. Additionally, an amorphous carbon layer forms and coats onto the surface of the graphite, contributing to excellent rate performance. The regenerated graphite (RG-1000) displays excellent rate performance, with capacities of 413 mAh/g at 50 mA g−1 and 102.1 mAh/g at 1000 mA g−1, respectively. Furthermore, it demonstrates long-term cycle stability, maintaining a capacity of 80 mAh/g at 1000 mA g−1 with a capacity retention of 78.4 % after 600 cycles. This RTS method enables rapid and efficient regeneration of spent graphite anodes for lithium-ion batteries, providing a facile and environmentally friendly strategy for their direct regeneration.

Direct regeneration of high-value LiFePO4 cathode materials with nitrogen doped carbon coating

Lithium iron phosphate (LiFePO4) batteries are currently becoming the primary power system for electric vehicles. However, after the life period, the heavy amounts of electric cars would give rise to a great number of scrapped LiFePO4 batteries, which inevitably causes serious environmental pollution and resources waste problems. Therefore, it is much imperative and urgent to develop the green technology for regenerating and recycling these scrapped LiFePO4 batteries. Herein, we reported an efficient and straightforward solid-phase strategy to achieve the direct regeneration of scrapped LiFePO4 cathode materials. The decommissioned LiFePO4 was successfully regenerated by adding lithium carbonate and melamine under the heat treatment condition, and the battery performance was repaired. The electrochemical performance of regenerated LiFePO4 is even higher than that of the unused LiFePO4 at 0.05 C. Moreover, the regenerated LiFePO4 also exhibits excellent capacity preservation rate of 99.03 % after 200 cycles and outstanding rate capability at 5 C with a discharge capacity of 116 mAh/g. The systematical study demonstrates that the nitrogen-doped carbon coatings play vital role in improving the properties of regenerated LiFePO4 cathode materials. This work provides a potential approach to resolve the scrapped LiFePO4 cathode materials to meet the coming retired tide of lithium ion batteries.

In vitro multiplication and phytochemical evaluation of Apios americana Medik for enhanced production of the staple food and tissues with versatile bioactivities

Apios americana Medik tissues, including tubers, flowers, leaves, and vines have both nutritional and therapeutic benefits. These tissues are extensively used in products like beverages and food supplements, driving an exponential increase in worldwide demand for the plant. However, conventional propagation of A. americana through seeds and tubers faces several challenges, including limited seed sets under manual pollination, resulting in reduced production. To overcome these challenges, micropropagation emerges as a promising solution. The current research study has developed an effective in vitro propagation strategy for A. americana using direct regeneration from apical segment explants. Full-strength Quoirin and Lepoivre (QL) medium, supplemented with vitamins and 2.0 mg/L benzylaminopurine (BAP), yielded the highest number of shoots (7.50 ± 0.06) per apical segment explant. QL medium fortified with 1.0 mg/L indole-3-butyric acid (IBA) demonstrated the highest root number (2.80 ± 0.30), length (85.80 ± 7.49 mm), and surface area (10.40 ± 0.82 cm2) in regenerated A. americana shoots. The survival rate of the regenerants in the ex vitro environment was 92.7% after acclimatization. In vitro-regenerated A. americana plants and mother plants exhibited similar ploidy level, chlorophyll content, photosynthetic rate, phytochemical composition, and antioxidant capacity, indicating similarity in their physiological and biochemical properties. This protocol offers a rapid and scalable method for generating high-quality, A. americana plant stocks with stable genome size/ploidy level, meeting the exponentially growing demand for plant tissues. Additionally, it holds potential applications in A. americana breeding and germplasm preservation.

Direct Plant Regeneration from Nodal Explants of Grapefruit (Citrus paradisi Macfad.)

Aims: The present study was undertaken to develop a protocol for in vitro regeneration and multiplication of disease-free quality planting material of Grapefruit (Citrus paradisi Macfad.). Study Design:  Completely Randomized Design (CRD) Place and Duration of Study: The study was conducted at the Plant Tissue Culture Laboratory, Department of Horticulture, University of Agricultural Sciences, Gandhi Krishi Vignana Kendra, Bengaluru, from 2020 to 21. Methodology: Nodal segments from the young shoots of field growing plants were used as explants to conduct the experiment. The explants were sterilized and placed on MS medium supplemented with different concentrations and combinations of growth regulators, namely BAP, Kinetin and Gibberellic acid. Results: Among the different combinations of growth regulators, the combination of BAP 1.0 mgL-1 and GA3 3.0 mgL-1 produced maximum number of shoots (7) from nodal segments Conclusion: The use of growth regulators such as BAP and GA3 is reliable for shoot regeneration even when the field explants are used.

Fast Li Replenishment Channels-Assisted Recycling of Degraded Layered Cathodes with Enhanced Cycling Performance and Thermal Stability.

The direct recycling of cathode materials in lithium-ion batteries is important for environmental protection and resource conservation. The key regeneration processes are composition replenishment and atom rearrangement, both of which depend on the migration and diffusion of atoms. However, for the direct recycling of degraded LiNi0.5 Co0.2 Mn0.3 O2 (D-NCM523) cathode, the irreversible phase transitions that accumulate during the long-term cycles block the Li diffusion channels with a high diffusion energy barrier, making it difficult to fully repair the layered structure and resulting in rapid capacity decay. To address the challenge, fast Li replenishment channels are rebuilt to regulate the surface phase and effectively assist the regeneration process with a reduced energy barrier. This method reduces the amount of Li supplement by >75% and shortens the sintering time (only 2h) to fully regenerate D-NCM523, compared to general direct recycling methods. The regenerated NCM523 (LCMB-NCM523) exhibits a satisfactory repaired specific capacity of 160mAhg-1 and excellent cycling stability, retaining 78% of its capacity after 300 cycles. In addition, LCMB-NCM523 is recycled with improved thermal decomposition peak temperature and enables 200 cycles even at 60°C, greatly improving safety. This work proposes a promising way for the large-scale direct regeneration of layered cathodes.

Direct capacity regeneration for spent Li-ion batteries

Direct capacity regeneration for spent Li-ion batteries

Toward Direct Regeneration of Spent Lithium-Ion Batteries: A Next-Generation Recycling Method.

The popularity of portable electronic devices and electric vehicles has led to the drastically increasing consumption of lithium-ion batteries recently, raising concerns about the disposal and recycling of spent lithium-ion batteries. However, the recycling rate of lithium-ion batteries worldwide at present is extremely low. Many factors limit the promotion of the battery recycling rate: outdated recycling technology is the most critical one. Existing metallurgy-based recycling methods rely on continuous decomposition and extraction steps with high-temperature roasting/acid leaching processes and many chemical reagents. These methods are tedious with worse economic feasibility, and the recycling products are mostly alloys or salts, which can only be used as precursors. To simplify the process and improve the economic benefits, novel recycling methods are in urgent demand, and direct recycling/regeneration is therefore proposed as a next-generation method. Herein, a comprehensive review of the origin, current status, and prospect of direct recycling methods is provided. We have systematically analyzed current recycling methods and summarized their limitations, pointing out the necessity of developing direct recycling methods. A detailed analysis for discussions of the advantages, limitations, and obstacles is conducted. Guidance for future direct recycling methods toward large-scale industrialization as well as green and efficient recycling systems is also provided.

Preparation of bilayer tissue-engineered polyurethane/poly-L-lactic acid nerve conduits and their in vitro characterization for use in peripheral nerve regeneration

BackgroundDue to loss of peripheral nerve structure and/or function resulting from trauma, accidents, and other causes, peripheral nerve injuries continue to be a major clinical problem. These injuries can cause partial or total loss of sensory, motor, and autonomic capabilities as well as neuropathic pain. PNI affects between 13 and 23 out of every 100,000 people annually in developed countries. Regeneration of damaged nerves and restoration of function after peripheral nerve injury remain significant therapeutic challenges. Although autologous nerve graft transplantation is a viable therapy option in several clinical conditions, donor site morbidity and a lack of donor tissue often hinder full functional recovery. Biomimetic conduits used in tissue engineering to encourage and direct peripheral nerve regeneration by providing a suitable microenvironment for nerve ingrowth are only one example of the cutting-edge methods made possible by this field. Many innate extracellular matrix (ECM) structures of different tissues can be successfully mimicked by nanofibrous scaffolds. Nanofibrous scaffolds can closely mimic the surface structure and morphology of native ECMs of many tissues.MethodsIn this study, we have produced bilayer nanofibrous nerve conduit based on poly-lactic acid/polyurethane/multiwall carbon nanotube (PLA/PU/MWCNT), for application as composite scaffolds for static nerve tissue engineering. The contact angle was indicated to show the hydrophilicity properties of electrospun nanofibers. The SEM images were analyzed to determine the fiber’s diameters, scaffold morphology, and endometrial stem cell adhesion. Moreover, MTT assay and DAPI staining were used to show the viability and proliferation of endometrial stem cells.ResultsThe constructed bilayer PLA/PU/MWCNT scaffolds demonstrated the capacity to support cell attachment, and the vitality of samples was assessed using SEM, MTT assay, and DAPI staining technique.ConclusionsAccording to an in vitro study, electrospun bilayer PLA/PU/MWCNT scaffolds can encourage the adhesion and proliferation of human endometrial stem cells (hEnSCs) and create the ideal environment for increasing cell survival.

Direct organ regeneration from apical shoot buds of adult Pinus massoniana Lamb

Direct organ regeneration from apical shoot buds of adult Pinus massoniana Lamb

Optimization of an Efficient Direct Shoot Induction System and Histological Evaluation of Shoot Formation in Cucurbita maxima Duch

Improving plant regeneration ability and shortening regeneration time can promote the development of genetic transformation breeding technology for horticultural crops. We optimized several culture conditions, including explant type, mother plant genotype, and medium, to improve shoot formation in winter squash (Cucurbita maxima Duch.). Histological analysis of the occurrence of shoots was also carried out. The results indicate that cotyledon was the most suitable explant for inducing the shoot regeneration of winter squash. We found that ‘Jin-li’ had a shorter shoot induction time and a higher average number of shoots. The highest induction rate of 95.23% among the five lines. The average shoot induction rate of five lines was the highest (84.85%) on Murashige and Skoog (MS) medium supplemented with 2.0 mg/L 6-benzylaminopurine (6-BA) and 0.2 mg/L indole-3-acetic acid (IAA). We also found that there was an interaction between genotypes and induction media, and their interaction had a greater impact on the shoot induction rate than individual effects. Histological observation revealed that the induced shoots of winter squash cotyledons originated from subepidermal cells. We also found that the optimal medium for de novo root regeneration was 1/2 MS. We acclimatized and cultivated regenerated plants and harvested their fruits, which maintained the characteristics of mother plants. These findings lay an important foundation for further research on direct shoot regeneration and accelerate its application in winter squash genetic transformation.

Spatiotemporal modulation of nitric oxide and Notch signaling by hemodynamic-responsive Trpv4 is essential for ventricle regeneration

Zebrafish have a remarkable ability to regenerate injured hearts. Altered hemodynamic forces after larval ventricle ablation activate the endocardial Klf2a-Notch signaling cascade to direct zebrafish cardiac regeneration. However, how the heart perceives blood flow changes and initiates signaling pathways promoting regeneration is not fully understood. The present study demonstrated that the mechanosensitive channel Trpv4 sensed the altered hemodynamic forces in injured hearts and its expression was regulated by blood flow. In addition to mediating the endocardial Klf2a-Notch signal cascade around the atrioventricular canal (AVC), we discovered that Trpv4 regulated nitric oxide (NO) signaling in the bulbus arteriosus (BA). Further experiments indicated that Notch signaling primarily acted at the early stage of regeneration, and the major role of NO signaling was at the late stage and through TGF-β pathway. Overall, our findings revealed that mechanosensitive channels perceived the changes in hemodynamics after ventricle injury, and provide novel insights into the temporal and spatial coordination of multiple signaling pathways regulating heart regeneration.

Strong Oxidizing Molten Salts for Strengthening Structural Restoration Enabling Direct Regeneration of Spent Layered Cathode.

As a mainstream technology for recycling spent lithium-ion batteries, direct regeneration is rapidly developed due to its high efficiency and green characteristics. However, efficient reuse of spent LiNix Coy Mn1- x - y O2 cathode is still a significant challenge, as the rock salt/spinel phase on the surface hinders the Li replenishment and phase transformation to the layered structure. In this work, the fundamental understanding of the repair mechanism is confirmed that the oxidizing atmosphere is the crucial factor that can greatly improve the rate and degree of phase restoration. Particularly, a ternary-component molten salt system (LiOH-Li2 CO3 -LiNO3 ) is proposed for direct regeneration of LiNi0.5 Co0.2 Mn0.3 O2 (NCM523), which can in situ generate the strong oxidizing intermediate of superoxide radicals. Additionally, it shows a liquid-like reaction environment at a lower temperature to acceclerate the transport rate of superoxide-ions. Therefore, the synergistic effect of LiOH-Li2 CO3 -LiNO3 system can strengthen the full restoration of rock salt/spinel phases and achieve the complete Li-supplement. As anticipated, the regenerated NCM523 delivers a high cycling stability with a retention of 91.7% after 100 cycles, which is even competitive with the commercial NCM523. This strategy provides a facile approach for the complete recovery of layer structure cathode, demonstrating a unique perspective for the direct regeneration of spent lithium-ion batteries.

Synergistic Amelioration of Osseointegration and Osteoimmunomodulation with a Microarc Oxidation-Treated Three-Dimensionally Printed Ti-24Nb-4Zr-8Sn Scaffold via Surface Activity and Low Elastic Modulus.

Biomaterial scaffolds, including bone substitutes, have evolved from being primarily a biologically passive structural element to one in which material properties such as surface topography and chemistry actively direct bone regeneration by influencing stem cells and the immune microenvironment. Ti-6Al-4V(Ti6Al4V) implants, with a significantly higher elastic modulus than human bone, may lead to stress shielding, necessitating improved stability at the bone-titanium alloy implant interface. Ti-24Nb-4Zr-8Sn (Ti2448), a low elastic modulus β-type titanium alloy devoid of potentially toxic elements, was utilized in this study. We employed 3D printing technology to fabricate a porous scaffold structure to further decrease the structural stiffness of the implant to approximate that of cancellous bone. Microarc oxidation (MAO) surface modification technology is then employed to create a microporous structure and a hydrophilic oxide ceramic layer on the surface and interior of the scaffold. In vitro studies demonstrated that MAO treatment enhances the proliferation, adhesion, and osteogenesis capabilities on the scaffold surface. The chemical composition of the MAO-Ti2448 oxide layer is found to enhance the transcription and expression of osteogenic genes in bone mesenchymal stem cells (BMSCs), potentially related to the enrichment of Nb2O5 and SnO2 in the oxide layer. The MAO-Ti2448 scaffold, with its synergistic surface activity and low stiffness, significantly activates the anti-inflammatory macrophage phenotype, creating an immune microenvironment that promotes the osteogenic differentiation of BMSCs. In vivo experiments in a rabbit model demonstrated a significant improvement in the quantity and quality of the newly formed bone trabeculae within the scaffold under the contact osteogenesis pattern with a matched elastic modulus. These trabeculae exhibit robust connections to the external structure of the scaffold, accelerating the formation of an interlocking structure between the bone and implant and providing higher implantation stability. These findings suggest that the MAO-Ti2448 scaffold has significant potential as a bone defect repair material by regulating osteoimmunomodulation and osteogenesis to enhance osseointegration. This study demonstrates an optional strategy that combines the mechanism of reducing the elastic modulus with surface modification treatment, thereby extending the application scope of β-type titanium alloy.

Dynamic Li+ Capture through Ligand-Chain Interaction for the Regeneration of Depleted LiFePO4 Cathode.

After application in electric vehicles, spent LiFePO4 (LFP) batteries are typically decommissioned. Traditional recycling methods face economic and environmental constraints. Therefore, direct regeneration has emerged as a promising alternative. However, irreversible phase changes can significantly hinder the efficiency of the regeneration process owing to structural degradation. Moreover, improper storage and treatment practices can lead to metamorphism, further complicating the regeneration process. In this study, a sustainable recovery method is proposed for the electrochemical repair of LFP batteries. A ligand-chain Zn-complex (ZnDEA) is utilized as a structural regulator, with its ─NH─ group alternatingly facilitating the binding of preferential transition metal ions (Fe3+ during charging and Zn2+ during discharging). This dynamic coordination ability helps to modulate volume changes within the recovered LFP framework. Consequently, the recovered LFP framework can store more Li-ions, enhance phase transition reversibility between LFP and FePO4 (FP), modify the initial Coulombic efficiency, and reduce polarization voltage differences. The recovered LFP cells exhibit excellent capacity retention of 96.30% after 1500 cycles at 2C. The ligand chain repair mechanism promotes structural evolution to facilitate ion migration, providing valuable insights into the targeted ion compensation for environmentally friendly recycling in practical applications.

Multiscale observations on mechanisms for direct regeneration of degraded NCM cathode materials

The direct regeneration of degraded cathode materials in spent lithium-ion batteries (LIBs) is an environmentally sustainable and cost-effective strategy to “make waste be wealth”. However, the microscopic regeneration mechanisms and kinetics for this process are almost elusive. In this paper, we attempt to fully extract the regeneration mechanisms during direct regeneration of degraded NCM 523 (LiNi0.5Co0.2Mn0.3O2) materials in a multiscale manner. A series of in situ (TEM, SEM, synchrotron XPS) and ex situ (TEM & EDS tomography, electrochemical measurements) characterization techniques are used for establishing the complete physicochemical picture of NCM 523 regeneration. Important dynamical details across atomic-scale, nanoscale, microscale, and single-particle level including reverse transformation from rock salt to layered phase, healing of defects (pores and cracks), and valence transformations of metal ions are followed and discussed, which is further supplemented by systematical theoretical analysis as well as full-cell electrochemical tests. This study provides an in-depth understanding toward the direct regeneration of degraded cathode materials and may shed light on the future development and optimization of direct regeneration strategies.

COTiR: Molecular Communication Model for Synthetic Exosome-Based Tissue Regeneration.

Mesenchymal stem cell (MSC)-derived exosomes are recognized as an unparalleled therapy for tissue damage rendered by COVID-19 infection and subsequent hyper-inflammatory immune response. However, the natural targeting mechanism of exosomes is challenging to detect the damaged tissue over long diffusion distances efficiently. The coordinated movement of exosomes is desired for successful identification of target sites. In this work, we propose a molecular communication model, CoTiR, with a bio-inspired directional migration strategy (DMS) for guided propagation of exosomes to target the damaged tissues. The model includes directional propagation, reception, and regeneration of tissue. The proposed model has the potential to be used in designing efficient communication systems in the nanodomain. We compare the proposed model to the basic random propagation model and show the efficacy of our model regarding the detection of multiple targets and the detection time required. Simulation results indicate that the proposed model requires a shorter period of time for a similar number of exosomes to detect the targets compared to the basic random propagation model. Furthermore, the results reveal a 99.96% decrease in the collagen concentration in the absence of inflammatory cytokine molecules compared to the collagen concentration in the presence of inflammatory cytokine molecules.

Direct regeneration of spent graphite anode material via a simple thermal treatment method

This work reports a novel method for recycling spent graphite. The regenerated graphite exhibits a discharge capacity of 366 mA h g−1 at 1C.

Somatic Embryogenesis and Direct Shoot Bud Formation from in vitro Root Segments of Garlic (Allium sativum L.)

In vitro techniques are unconventionally used for garlic improvement. In garlic tissue culture, numerous roots are produced in vitro. Segments (1 cm) of those in vitro roots were cultivated on MS medium with 5.0 μM 2, 4-D for callus initiation followed by transfer to 0.5 μM 2, 4-D for somatic embryogenesis. Root segments had 51.67% callus and somatic embryo formation. Plantlet regeneration was obtained from 90% calli after being transferred to MS medium supplemented with 5.0 μM kinetin. Within 6 months, 54.8 plants per root segment and 42.2 plants per root tip explant were found. MS media supplemented with 1.0 or 5.0 μM NAA in combination with 10.0 or 50.0 μM BA were used for direct shoot bud induction from root segments. The highest percentage (23.33 %) of direct shoot bud regeneration was found in 5.0 μM NAA with 50.0 μM BA within 2 months. The number of shoots per explant was varied from 1-81 with the highest average of 15.75 shoots per explant. The shoots produced bulblets upon transfer to a medium containing higher amount of sucrose (12%). The largest bulblets weighed 356.57 g in the medium with 5.0 μM NAA and 50.0 μM BA. In both pathways, regeneration occurred from only the apical (distal) end of the root segments. The protocols are promising for continuous regeneration of propagules and genetic transformation study for improvement of garlic. Plant Tissue Cult. & Biotech. 33(2): 135-142, 2023 (December)