Lithium Diffusion Research Articles

Exploring high-valence element doping in LLZO electrolytes: Effects on phase transition and lithium-ion conductivity

The increasing popularity of electric vehicles and the emergence of 5G technology have created a demand for high-energy-density and safe batteries. Among various solid-state electrolytes, crystalline Li7La3Zr2O12 (c-LLZO) has garnered significant attention due to its exceptional properties. Researchers have explored doping in LLZO to modulate its phase transition and enhance lithium-ion conductivity. However, the mechanism by which doping induces a phase change and affects lithium-ion conductivity is currently unclear. In this study, we investigated LLZO doping and discovered that high-valence-element doping introduces vacancies, destabilizing the tetragonal phase and promoting the formation of the stable cubic phase. Moreover, we found that the introduction of lithium-ion vacancies significantly enhances lithium-ion conductivity. Nevertheless, doping also has adverse effects. Ga and Al dopants occupy the crucial Li24d sites, impeding lithium-ion diffusion and resulting in the closure of diffusion channels. Additionally, doping reduces the effective vacancy concentration within the structure, further restricting lithium-ion conductivity. In summary, our work elucidates the mechanism behind the influence of dopants on lithium-ion diffusion in LLZO.

Facile synthesis of SiOx/C as high-performance anodes for lithium-ion batteries

Despite its high capacity (∼2615 mAh·g−1), silicon oxide (SiOx) suffers from low electrical conductivity and volume expansion during cycling, leading to capacity fading. In this work, a SiOx/C composite was synthesized by magnesium thermal reduction using co-assembled mesoporous SiO2 and graphitic carbon nitride (g-C3N4) as precursors. The SiOx/C composite displays a sheet-like nanostructure with highly dispersed SiOx. The presence of carbon enhances the conductivity and structural stability of the composite, leading to a low charge resistance (94.0 Ω), fast lithium diffusion (DLi+ = 5.15 × 10−14 cm2·s−1), and excellent cycling capability (863 mAh·g−1 after 160 cycles).

Two‐Dimensional Graphitic Carbon‐Nitride (g‐C3N4)‐Coated LiNi0.8Co0.1Mn0.1O2 Cathodes for High‐Energy‐Density and Long‐Life Lithium Batteries

High‐capacity nickel‐rich layered oxides are promising cathode materials for high‐energy‐density lithium batteries. However, the poor structural stability and severe side reactions at the electrode/electrolyte interface result in unsatisfactory cycle performance. Herein, the thin layer of two‐dimensional (2D) graphitic carbon‐nitride (g‐C3N4) is uniformly coated on the LiNi0.8Co0.1Mn0.1O2 (denoted as NCM811@CN) using a facile chemical vaporization‐assisted synthesis method. As an ideal protective layer, the g‐C3N4 layer effectively avoids direct contact between the NCM811 cathode and the electrolyte, preventing harmful side reactions and inhibiting secondary crystal cracking. Moreover, the unique nanopore structure and abundant nitrogen vacancy edges in g‐C3N4 facilitate the adsorption and diffusion of lithium ions, which enhances the lithium deintercalation/intercalation kinetics of the NCM811 cathode. As a result, the NCM811@CN‐3wt% cathode exhibits 161.3 mAh g−1 and capacity retention of 84.6% at 0.5 C and 55 °C after 400 cycles and 95.7 mAh g−1 at 10 C, which is greatly superior to the uncoated NCM811 (i.e. 129.3 mAh g−1 and capacity retention of 67.4% at 0.5 C and 55 °C after 220 cycles and 28.8 mAh g−1 at 10 C). The improved cycle performance of the NCM811@CN‐3wt% cathode is also applicable to solid–liquid‐hybrid cells composed of PVDF:LLZTO electrolyte membranes, which show 163.8 mAh g−1 and the capacity retention of 88.1% at 0.1 C and 30 °C after 200 cycles and 95.3 mAh g−1 at 1 C.

Improved electrochemical performance of Cu-Sn/nano-SiO2 composite anode materials for lithium-ion batteries fabricated by controlled electrodeposition

Cu-Sn/nano-SiO2 composite materials are fabricated through electrodeposition process coupled with precise thermal treatment, which employs hexadecyl trimethyl ammonium bromide to guarantee the even distribution of nano-SiO2 particles within the Cu-Sn alloy framework. The characterization results indicate that integrating nano-SiO2 into the Cu-Sn matrix effectively prevents active particles from detaching from the copper foil current collector. By adjusting the current density, the electrochemical performance of the Cu-Sn/nano-SiO2 composite electrode is significantly enhanced. Specifically, the initial charge and discharge specific capacities of the composite electrolyte are approximately 746.6 and 1470.8 mAh/g at 100 mA/g, respectively. Moreover, the cell can still maintain a discharge specific capacity of 358.6 mAh/g after 100 cycles. Furthermore, the cell demonstrates an improved lithium-ion diffusion coefficient of approximately 9.639 × 10–15 cm²/s and a lower transfer resistance of 54.65 Ω. Therefore, a direct approach of fabricating the Cu-Sn/nano-SiO2 composite electrode with enhanced electrochemical properties may provide valuable guidance for alloy anodes in the energy storage field.

Synergetic electrochemical behavior of magnesium-doped ZnO nanorods with reduced graphene oxide

In this study, we synthesized magnesium-doped ZnO (Mg-ZnO) nanorods embedded in reduced oxide graphene layers (rGO) using the simplest one-pot hydrothermal method. The composites ZnO/rGO and Mg-doped ZnO-rGO (Mg-ZnO/rGO) are polycrystalline and showed successful doping of Mg in ZnO lattice which expands the ZnO lattice structure helping lithium storage by providing more sites. Mg doping in the ZnO lattice extenuates ZnO volume contraction and expansion which promotes structural stabilization of the electrode during multiple charging-discharging cycles. In composites, ZnO and Mg-ZnO attain the shape of nanorods and tightly interleaved theirselves in the sheet of rGO. XPS showed the dominant peak of C1s of sp2 bonding supporting the formation of reduced GO along with Zn, O and Mg elements. The performance of the materials is evaluated as anode for LIB. The ZnO/rGO anode exhibits a discharge capacity of 445 mAh/g at 100 mA g−1 that was significantly enhanced to 463 mAh/g after doping ZnO with 2 % Mg. With further increasing the concentration of Mg to 4 %, the Mg-ZnO/rGO anode achieves a higher discharge capacity of 520 mAh g−1 with better rate capability than its counterpart electrodes. The synergistic effects between Mg-ZnO and carbon-based nanomaterials are ascribed to the creation of additional contact sites to penetrate electrolyte ions into the electrode, thus resulting in the fast lithium-ion diffusion rate.

Melamine Polymerization Promotes Compact Phosphorus/Carbon Composite for High-Performance and Safe Lithium Storage.

Phosphorus is regarded as a promising material for high-performance lithium-ion batteries (LIBs) due to its high theoretical capacity, appropriate lithiation potential, and low lithium-ion diffusion barrier. Phosphorus/carbon composites (PC) are engineered to serve as high-capacity high-rate anodes; the interaction between phosphorus and carbon, long-term capacity retention, and safety problems are important issues that must be well addressed simultaneously. Herein, an in situ polymerization approach to fabricate a poly-melamine-hybridized (pMA) phosphorus/carbon composite (pMA-PC) is employed. The pMA hybridization enhances the density and electrical conductivity of the PC, improves the structural integrity, and facilitates stable electron transfer within the pMA-PC composite. Moreover, the pMA-PC composite exhibits efficient adsorption of lithium polysulfides, enabling stable transport of Li+ ions. Therefore, the pMA-PC anode demonstrates a high specific charging capacity of 1,381mAhg-1 at 10Ag-1, and a great capacity retention of 86.7% at 1Ag-1 over 500 cycles. The synergistic effect of phosphorus and nitrogen further confers excellent flame retardant properties to the pMA-PC anode, including self-extinguishing in 2.5s, and a much lower combustion temperature than PC. The enhanced capacity and safety performance of pMA-PC show potential in future high-capacity and high-rate LIBs.

Boron-manganese-nitrogen co-doped three-dimensional porous carbon realizes superior capacitive lithium-ion storage

Three-dimensional (3D) porous carbon has sufficient specific surface area and anchor positioning points. The pore structure facilitates uniform charge distribution, and buffers volume changes during stripping. However, single carbon materials have limited theoretical capacity and short cycle life. Here, 3D porous carbon material BCN/Mn-6 (B,N and Mn co-doped porous carbon with 6 mmol Mn content) co-doped with manganese, boron and nitrogen was synthesized by heat treatment. Affective modulation of the material structure and surface functional groups was achieved by adjusting the amount of manganese doping. The metal element doping can promote the diffusion of lithium ions, and the formed vacancies and defects can be used as lithium storage sites. Nitrogen doping can improve the dispersion and stability of metals and oxides, and regulate the redox capacity. Co-doping of metals and heteroatoms synergistically improves electrical conductivity. Thus, BCN/Mn-6 exhibits excellent cycling stability (99.60 % Coulombic efficiency after 300 cycles) and specific capacity (779.9 mAh/g), and shows capacity rise. This study provides a new direction for the preparation of carbon-based electrode materials doped with heteroatoms and the study of capacitive energy storage mechanisms.

The impact of magnesium content on lithium-magnesium alloy electrode performance with argyrodite solid electrolyte

Solid-state lithium-based batteries offer higher energy density than their Li-ion counterparts. Yet they are limited in terms of negative electrode discharge performance and require high stack pressure during operation. To circumvent these issues, we propose the use of lithium-rich magnesium alloys as suitable negative electrodes in combination with Li6PS5Cl solid-state electrolyte. We synthesise and characterise lithium-rich magnesium alloys, quantifying the changes in mechanical properties, transport, and surface chemistry that impact electrochemical performance. Increases in hardness, stiffness, adhesion, and resistance to creep are quantified by nanoindentation as a function of magnesium content. A decrease in diffusivity is quantified with 6Li pulsed field gradient nuclear magnetic resonance, and only a small increase in interfacial impedance due to the presence of magnesium is identified by electrochemical impedance spectroscopy which is correlated with x-ray photoelectron spectroscopy. The addition of magnesium aids contact retention on discharge, but this must be balanced against a decrease in lithium diffusivity. We demonstrate via electrochemical testing of symmetric cells at 2.5 MPa and 30∘C that 1% magnesium content in the alloy increases the stripping capacity compared to both pure lithium and higher magnesium content alloys by balancing these effects.

Probing the range of applicability of structure- and energy-adjusted QM/MM link bonds III: QM/MM MD simulations of solid-state systems at the example of layered carbon structures.

The previously introduced workflow to achieve an energetically and structurally optimized description of frontier bonds in quantum mechanical/molecular mechanics (QM/MM)-type applications was extended into the regime of computational material sciences at the example of a layered carbon model systems. Optimized QM/MM link bond parameters at HSEsol/6-311G(d,p) and self-consistent density functional tight binding (SCC-DFTB) were derived for graphitic systems, enabling detailed investigation of specific structure motifs occurring in graphene-derived structures quantum-chemical calculations. Exemplary molecular dynamics (MD) simulations in the isochoric-isothermic (NVT) ensemble were carried out to study the intercalation of lithium and the properties of the Stone-Thrower-Wales defect. The diffusivity of lithium as well as hydrogen and proton adsorption on a defective graphene surface served as additional example. The results of the QM/MM MD simulations provide detailed insight into the applicability of the employed link-bond strategy when studying intercalation and adsorption properties of graphitic materials.

MoS2-C superlattice cathodes for conductive additive-free sulfide electrolyte-based all-solid-state lithium batteries

Sulfide electrolytes play a crucial role in the pursuit of high-performance all-solid-state lithium batteries (ASSLBs). However, most sulfide electrolytes have intrinsic narrow electrochemical stability windows, and decomposition reactions are thermodynamically favorable, especially contact with conductive additive. These ongoing side reactions accelerate sulfide electrolytes degradation, posing a significant threat to the cycling stability of ASSLBs. Herein, we propose an effective approach to address this challenge by designing a MoS2-C superlattice structure. This architecture, characterized by a layer-by-layer inter-stacking of MoS2 nanosheets and carbon layers, endows it with excellent electronic conductivity and enhanced lithium diffusion kinetics. Leveraging this superlattice, ASSLBs incorporating MoS2-C superlattice as the cathode without conductive additive exhibit a substantial improvement in electrochemical performance, ultimately achieving a conductive additive-free ASSLB. Remarkably, the conductive additive-free ASSLBs based on the MoS2-C superlattice demonstrates outstanding stability, enduring 300 cycles with a capacity retention of 96.8 % at a 1 C rate. This enhancement can be attributed to the improved charge transfer kinetics of MoS2-C superlattice and the effective suppression of side reactions between the sulfide electrolyte and conductive additive. Our study presents a promising design strategy to achieve high-rate performance and tackle long-term challenges in the application of sulfide electrolytes-based ASSLBs.

High-throughput investigation of stability and Li diffusion of doped solid electrolytes via neural network potential without configurational knowledge

Solid electrolytes hold substantial promise as vital components of all-solid-state batteries. Enhancing their performance necessitates simultaneous improvements in their stability and lithium conductivity. These properties can be calculated using first-principles simulations, provided that the crystal structure of the material and the diffusion pathway through the material are known. However, solid electrolytes typically incorporate dopants to enhance their properties, necessitating the optimization of the dopant configuration for the simulations. Yet, performing such calculations via the first-principles approach is so costly that existing approaches usually rely on predetermined dopant configurations informed by existing knowledge or are limited to systems doped with only a few atoms. The proposed method enables the optimization of the dopant configuration with the support of neural network potential (NNP). Our approach entails the use of molecular dynamics to analyze the diffusion after the optimization of the dopant configuration. The application of our approach to Li10\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${_{10}}$$\\end{document}MP2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${_{2}}$$\\end{document}S12-x\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${_{12-x}}$$\\end{document}Ox\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${_{x}}$$\\end{document} (M = Ge, Si, or Sn) reproduce the experimental results well. Furthermore, analysis of the lithium diffusion pathways suggests that the activation energy of diffusion undergoes a percolation transition. This study demonstrates the effectiveness of NNPs in the systematic exploration of solid electrolytes.

Damage-Tolerant and Self-Repairing Web-Like Borate Type Binder Enable Stable Operation of Efficient Si-Based Anodes.

Novel binder designs are shown to be fruitful in improving the electrochemical performance of silicon (Si)-based anodes. However, issues with mechanical damage from dramatic volume change and poor lithium-ion (Li+) diffusion kinetics in Si-based materials still need to be addressed. Herein, an aqueous self-repairing borate-type binder (SBG) with a web-like architecture and high ionic conductivity is designed for Si and SiO electrodes. The 3D web-like architecture of the SBG binder enables uniform stress distribution, while its self-repairing ability promotes effective stress dissipation and mechanical damage repair, thereby enhancing the damage tolerance of the electrode. The tetracoordinate boron ions ( ) in the SBG binder boosts the Li transportation kinetics of Si-based electrodes. Based on dynamic covalent and ionic conductive boronic ester bonds, the diverse requirements of the binder, including uniform stress distribution, self-repairing ability, and high ionic conductivity, can be met by simple components. Consequently, the proposed straightforward multifunction design strategy for binders based on dynamic boron chemistry provides valuable insights into fabricating high-performance Si-based anodes.

Enhancing performance of silicon/graphene composites by transition lattice interfaces constructed using plasma

The silicon-based (Si) anodes have not widely used due to their low conductivity and severe irreversible volume changes until now. Graphene (G) is considered a promising material for inhibiting volume expansion and enhancing conductivity of Si, a large amount of work has been exploring effective composite of graphene and silicon. A new SiG composite structure (PB-SiG-1) with transition lattice interface is provided by N plasma assisted technique in this work. The phase interface undergoes lattice changes on the atomic scale with silicon, oxygen, and carbon bonding in new chemical bonds (Si-O-C). More importantly, the lattice spacing of Si (111) increases from 0.31 nm to 0.325 nm due to the insertion of carbon or oxygen atom into the Si body, which promotes the diffusion kinetics of lithium ions. This PB-SiG-1 exhibits better electrochemical performance with reversible specific capacity of 2013.9 mAh g−1 after 100 cycles at 0.2 A g−1, high capacity retention of 98.53% and coulombic efficiency of 99.4%. The multiple advanced in situ methods reveal that the PB-SiG-1 not only has the ability to quickly transfer ions, electrons, and form stable SEI, but also has a low irreversible volume expansion of 33.1 %. This proves that the transition lattice interface endows PB-SiG-1 with isotropy characteristic of lithium diffusion, leading to dynamically stable electrodes during cycles. This work proposes a Si-C composite structure with transition lattice interface, which opens a new insight for volume expansion and lithium transmission in Si-C composite.

Phase Evolution of Multi-Metal Dichalcogenides With Conversion-Alloying Hybrid Mechanism for Superior Lithium Storage.

Traditional lithium-ion battery (LIB) anodes, whether intercalation-type like graphite or alloying-type like silicon, employing a single lithium storage mechanism, are often limited by modest capacity or substantial volume changes. Here, the kesterite multi-metal dichalcogenide (CZTSSe) is introduced as an anode material that harnesses a conversion-alloying hybrid lithium storage mechanism. Results unveil that during the charge-discharge processes, the CZTSSe undergoes a comprehensive phase evolution, transitioning from kesterite structure to multiple dominant phases of sulfides, selenides, metals, and alloys. The involvement of multi-components facilitates electron transport and mitigates swelling stress; meanwhile, it results in formation of abundant defects and heterojunctions, allowing for increased lithium storage active sites and reduced lithium diffusion barrier. The CZTSSe delivers a high specific capacity of up to 2266mA h g-1 at 0.1 A g-1; while, maintaining a stable output of 116mA h g-1 after 10000 cycles at 20 A g-1. It also demonstrates remarkable low-temperature performance, retaining 987mA h g-1 even after 600 cycles at -40°C. When employed in full cells, a high specific energy of 562Wh kg-1 is achieved, rivalling many state-of-the-art LIBs. This research offers valuable insights into the design of LIB electrodes leveraging multiple lithium storage mechanisms.

High-Performance Dendrite-Free Lithium Metal Anode Based on Metal-Organic Framework Glass.

The performance of lithium metal batteries is severely hampered by uncontrollable dendrite growth and volume change within the anode. This work addresses these obstacles by introducing a novel strategy: applying an isotropic and internal grain-boundary-free layer, specifically, a metal-organic framework (MOF) glass layer with nano-porosity onto the electrochemically plated lithium metal anode. Both ab initio and classical molecular dynamics simulations indicate that the MOF glass layer makes the lithium transport smooth and uniform via its internal monolithic and interfacial advantages. This MOF glass layer with the fast and more uniform lithium diffusion in the monolithic interior and its interface enables dendrite-free lithium plating and stripping through surface confinement effect and interfacial effect. When employed in symmetric batteries, the achieved Li metal anode can operate over 300h at 1mAcm-2. The full batteries matched with LiFePO4 exhibit high capacity (148mAhg-1), excellent rate performance (61mAhg-1 at 5C), and outstanding cycling stability (with capacity retention of ≈90% after 1000 cycles). The full batteries matched with high-voltage LiCoO2 also show superior performances. Therefore, the strategy of utilizing a MOF glass layer enables the development of high-performance lithium metal anodes.

Mo-doping modulated cationic vacancy in Zn3V2O8 with enhanced electrochemical performance for lithium-ion batteries

Given diverse redox reactions and abundant raw materials, Zn3V2O8 with high specific capacity is considered as a potential anode material for lithium-ion batteries. Same as other transition metal oxides, Zn3V2O8 suffers from infertile conductivity, sluggish ion diffusion and fast capacity loss derived from volume expansion during discharge/charge process, further hindering its application. In this work, a novel Mo doped Zn3V2O8 (Zn3V2-xMo5x/6O8) anode material with cationic vacancy (V vacancy) has been designed through a facile sol-gel method. It is found that a small Mo-doping amount has nearly no influence on the crystal structure, morphology and element valence states of Zn3V2O8. Mo doped Zn3V2O8 samples possess smaller charge transfer resistance and higher lithium ion diffusion coefficient. The results of electrochemical performance illustrate that Mo doped Zn3V2O8 can deliver higher reversible specific capacities and better rate capability compared with Zn3V2O8, which can be ascribed to the introduction of V vacancy. In particular, when Mo-doping amount is set as 0.03, the obtained Zn3V1.97Mo0.025O8 exhibits a reversible capacity of 481.1 mAh g−1 after 600 cycles at 1 A g−1. It is believed that this work could provide an effective and feasible strategy to construct high performance transition metal vanadate anode materials for lithium-ion batteries.

Effects of Ti4+ doping on electrochemical properties of LiNi0.815Co0.15Al0.035O2 cathode materials

The high nickel ternary cathode materials LiNi0.815Co0.15Al0.035O2 (NCA) have been widely used in Li-ion batteries due to their high energy density, low cost, and little environmental pollution. However, it suffers from rapid capacity degradation and poor charging rate. In this work, Ti4+ doping NCA cathode materials are prepared by the high-temperature solid-state method. The results show that 0.5%Ti-NCA has a lower cationic mixing degree and better cycling performance. The capacity retention rate of 100 cycles is 98.91% and 96.59% at current densities of 0.5 C and 1.0 C, respectively. The CV and EIS test results show that 0.5%Ti-NCA has lower polarization and higher lithium ion diffusion coefficient DLi+(8.43×10−14 cm2/S) after 100 cycles, while Pure-NCA only has 6.92×10−15 cm2/S, which effectively enhances the electrochemical properties of NCA cathode materials.

Li-ion storage chemistry of metal layers influences on metal oxides

A suitable current collector is a critical criterion for attaining high areal capacity in lithium batteries (LIBs). Here, we discover that the transition metal foam-type current collectors and their corresponding active materials upon a simple oxidation process, enable us to design a strategy for controlling the thickness of active materials toward achieving high areal capacity LIBs. Taking nickel foam (NiF) as a case study, we demonstrated that by calcining it in the air at different temperatures of 500 ℃, 600 ℃, 700 ℃, and 800 ℃, the electrodes exhibit distinct physical properties such as the thickness of active material layers, mechanical strength, and electrochemical properties including the rate capabilities, pseudocapacitive contribution, and lithium-ion diffusion. Ultimately, the optimized anode calcined at 700 °C (700-NiO@NiF) maintains a high reversible areal capacity of 7.6 mAh cm−2@0.4 mA cm−2, and 2.0 mAh cm−2 after 200 cycles@3.0 mA cm−2, We further verify that both cobalt foam and copper foam exhibited similar features like that of NiF by tuning their annealing temperatures, creating more opportunities for maximizing the areal capacity of LIBs.

Functionalized γ-Boehmite Covalent Grafting Modified Polyethylene for Lithium-Ion Battery Separator.

In the field of lithium-ion batteries, the challenges posed by the low melting point and inadequate wettability of conventional polyolefin separators have increased the focus on ceramic-coated separators. This study introduces a highly efficient and stable boehmite/polydopamine/polyethylene (AlOOH-PDA-PE) separator. It is crafted by covalently attaching functionalized nanosized boehmite (γ-AlOOH) whiskers onto polyethylene (PE) surfaces. The presence of a covalent bond increases the stability at the interface, while amino groups on the surface of the separator enhance the infiltration of the electrolyte and facilitate the diffusion of lithium ions. The PE-PDA-AlOOH separator, when used in lithium-ion batteries, achieves a discharge capacity of 126 mAh g-1 at 5 C and retains 97.1% capacity after 400 cycles, indicating superior cycling stability due to its covalently bonded ceramic surface. Thus, covalent interface modification is a promising strategy to prevent delamination of ceramic coatings in separators.

Mechanistic Understanding of Sieving Lithium Ions Using a Biobased Sorbent Technology for Sustainable Lithium Reclamation and Cleansing Brines.

Low-cost environmentally benign materials that can be produced in a large scale to extract lithium from brine resources could drive the lithium market toward a clean technology with high lithium recovery and production. Herein, we have investigated the utilization of a novel, environmentally benign, and low-cost biobased sorbent for the extraction of lithium from lithium-rich solutions. This biobased molecular sieving sorbent, iron(III)-tannate (Fe(III)-TA), belongs to a novel class of coordination polymer frameworks derived from a natural polyphenol-tannic acid (TA)-coordinated with iron(III) metal cations. Its lithium adsorption and kinetic isotherm studies conducted using lithium-rich aqueous solutions confirm the sorbent's dual function for lithium sieving via physisorption, chemisorption, and mass transfer diffusion processes. The adsorption equilibrium and kinetic isotherm models combined with the external and internal mass transfer diffusion models reveal a mechanistic pathway for lithium-ion adsorption. Aiding by forming a fluid film for external mass transfer diffusion of lithium ions, analytes adsorb onto the sorbent surface via physisorption and chemisorption followed by the internal mass transfer diffusion, occupying lithium ions in the sorbent's pores. The lithium adsorption efficiency studies conducted for brines with different concentrations of interference alkali and alkaline cations evidence that the sorbent's affinity for lithium ions strongly depends on the analyte concentration. The results evidence that the sorbent has the ability to lower the brine's salinity and significantly reduces the ratios of Mg/Li and Ca/Li by 4-fold and 10-fold, respectively, yielding lithium-rich solutions. Thus, implementing this innovative biobased sorbent technology as an add-in step into traditional lithium extraction and refining processes, one can design a cost-effective pathway to yield lithium-rich leachate by reducing the Mg/Li and Ca/Li ratio. Nonetheless, the present work demonstrates that Fe(III)-tannate is an effective multifunctional sorbent for sieving lithium from lithium-rich aqueous solutions as well as for desalinating brine resources to recover usable water. Thus, this biobased sorbent offers the possibility of effective application of lithium reclamation and remediation of brine, mitigating the environmental impact of brine discharge and large volume of freshwater usage for lithium extraction and refining.