Lithium-containing Compounds Research Articles

Corrosion evaluation of austenitic stainless steels in Li2CO3-K2CO3 eutectic salt for thermal energy storage

Molten carbonate salt is one of the promising candidates for high-temperature thermal energy storage tailored towards advanced pumped-thermal energy storage and next generation concentrated solar power technologies. However, severe corrosion of structural materials exposed to molten carbonate salts poses one of the most pivotal threats in terms of limiting their large-scale application at ever-escalating temperatures. Here, we elaborate the compatibility of three commercial austenitic stainless steels specifically SS310, SS316L and Incoloy 625 with Li2CO3-K2CO3 (28–72 wt%) eutectic salt. The corrosion behavior and corrosion mechanism of Fe-Cr (SS316L), Fe-Cr-Ni (SS310) and nickel-based (In625) alloys at 600 °C in air were also investigated. It revealed that SS310 exhibited better corrosion resistance compared to SS316 and In625, with weight loss of 23.8 mg/cm2 and corrosion rate of 522 μm/year after 500 h of exposure at 600 °C. This implies that higher Ni content of the alloy may not necessarily improve the corrosion resistance, it is associated with the basicity of the molten and the solubility of Ni salt in the melt. ICP analysis indicated that the salts exposed to SS310 and In625 at the same exposure time both had nearly 11 times more Ni than that exposed to SS316. Precisely, it is related to the behavior of the Cr-enriched zones formed in the corrosion layers of different alloys. The corrosion mechanism of SS310 specimens in molten carbonate can be generally divided into the following steps: (i) selective oxidation of the metal elements and lithiation reactions of the metal oxides to generate a passivation scale, (ii) an ever-growing middle transition scale consisted of mixed metal oxides and lithium-containing compounds, (iii) cracking and peeling off of the corrosion scale.

Li-metal free “in aqua” lithiation and re-lithiation of protected graphite anode for 4-V class aqueous lithium-ion capacitor

Lithium-ion capacitors, typically composed of a capacitive cathode and a pre-lithiated graphite anode in non-aqueous electrolyte, are promising power sources for energy harvesting applications with higher energy densities than standard electrochemical double layer capacitors. Superior energy density can be achieved by using pseudocapacitive cathodes in an aqueous electrolyte coupled with a water-stable protected anode. Lithiation of the graphite anode is one of the performance-governing processes influencing the working voltage, energy density, and cyclability of such power sources. Here, we report an effective, time-efficient, and safe lithiation procedure without the need of lithium metal or lithium-containing compounds as electrodes. The “in aqua” electrochemical lithiation of graphite is performed by using an over-sized activated carbon cathode and the salt dissolved in the aqueous electrolyte as the source of lithium ions. Subsequently, the protected anode (LixC6 + Li) is used as the counter electrode in an aqueous hybrid supercapacitor showing ∼70 % of capacity retention after 10,000 cycles. Nonetheless, the cycle life and capacity retention of the protected anode was further extended via an “in aqua” re-lithiation process allowing a 95 % retention of the initial capacity after 10,000 galvanostatic charge/discharge cycles.

Nanodiamond-modified separators and optimized graphene anodes for highly enhanced performance of lithium-ion batteries

As one of the core components in lithium-ion batteries (LIBs), upgraded separators are of great demand to further improve the performance of LIBs. This work designed two types of polypropylene (PP) separators modified by nanodiamonds (NDs) and NDs/ZnCO3 (named DPP and DZPP separators, respectively) used to enhance the performance of LIBs. LIBs with the modified separators possess excellent cycling stabilities and high specific capacities at various current densities (739 mA h g−1 for DPP-LIBs and 910 mA h g−1 for DZPP-LIBs after 1000 cycling processes at a rate of 2 C), which are significantly superior as compared to LIBs with traditional PP separators (460 mA h g−1). NDs are favorable for building novel buffer layers on the modified separators during the cycling processes, resulting in uniform depositions of lithium-containing compounds. Furthermore, NDs migrate to graphite anodes and enhance the specific area of the anodes through forming few-layered graphene. The in-situ lithiation of ZnCO3 creates an additional Li2CO3 layer on the DZPP separators, which serves as a buffer layer to redistribute Li-ions during the cycling processes of DZPP-LIBs. It is demonstrated that the deposition of NDs and/or NDs/ZnCO3 on PP separators provides a feasible, low-cost, and highly efficient method to improve the performance of LIBs.

Quantifying lithium lost to plating and formation of the solid-electrolyte interphase in graphite and commercial battery components

A key degradation mechanism in lithium-ion batteries (LIBs) is the irreversible loss of cyclable lithium during cycling. At the graphite negative electrode, this loss occurs through the deposition of lithium-containing compounds in the solid-electrolyte interphase (SEI) and through plating of metallic lithium, resulting in so-called dead lithium. The separate quantification of SEI and dead lithium has so far been a challenge in post mortem analysis of commercial LIBs. Here we report a simple and fast 7Li nuclear magnetic resonance spectroscopy (NMR) protocol applied to solid-state samples derived from lab-built batteries to independently quantify these and other lithium species in graphite electrodes without the need for specialized cell design nor knowledge of prior charging history. The metallic lithium content is corroborated by electrochemical calculations; the total amount of lithium is also determined from 7Li liquid-state NMR and inductively coupled plasma optical emission spectroscopy (ICP-OES) in suitably digested samples. Factors influencing accuracy like the sample handling process, the radiofrequency skin effect, and re-intercalation losses are investigated. Measurements on samples from commercial cells aged under realistic conditions demonstrate quantification of dead lithium and remaining ionic species (SEI), and further reveal lithium dendrites entrained in the separator following cell disassembly. The method uses conventional and widely available NMR instrumentation and is applicable to samples from lab-scale test cells or commercial batteries, thereby presenting a vast improvement over prior post mortem methods.

High-ICE and High-Capacity Retention Silicon-Based Anode for Lithium-Ion Battery.

Silicon-based anodes are promising to replace graphite-based anodes for high-capacity lithium-ion batteries (LIB). However, the charge–discharge cycling suffers from internal stresses created by large volume changes of silicon, which form silicon-lithium compounds, and excessive consumption of lithium by irreversible formation of lithium-containing compounds. Consumption of lithium by the initial conditioning of the anode, as indicated by low initial coulombic efficiency (ICE), and subsequently continuous formation of solid-electrolyte-phase (SEI) on the freshly exposed silicon surface, are among the main issues. A high-performance, silicon-based, high-capacity anode exhibiting 88.8% ICE and the retention of 2 mAh/cm2 areal capacity after 200 discharge–charge cycles at the rate of 1 A/g is reported. The anode is made on a copper foil using a mixture of 70%:10%:20% by weight ratio of silicon flakes of 100 × 800 × 800 nm in size, Super P conductivity enhancement additive, and an equal-weight mixture of CMC and SBR binders. Pyrolysis of fabricated anodes at 700 °C in argon environment for 1 h was applied to convert the binders into a porous graphitic carbon structure that encapsulates individual silicon flakes. The porous anode has a mechanically strong and electrically conductive graphitic carbon structure formed by the pyrolyzed binders, which protect individual silicon flakes from excessive reactions with the electrolyte and help keep small pieces of broken silicon flakes together within the carbon structure. The selection and amount of conductivity enhancement additives are shown to be critical to the achievement of both high-ICE and high-capacity retention after long cycling. The Super P conductivity enhancement additive exhibits a smaller effective surface area where SEI forms compared to KB, and thus leads to the best combination of both high-ICE and high-capacity retention. A silicon-based anode exhibiting high capacity, high ICE, and a long cycling life has been achieved by the facile and promising one-step fabrication process.

Revealing the spatial and temporal distribution of different chemical states of lithium by EELS analysis using non-negative matrix factorization

Detection of the spatial distribution and temporal evolution of an element in different chemical states is difficult in transmission electron microscopy. Here, taking the lithium element as an example, spatial and temporal distribution of different lithium-containing compounds could be revealed by using electron energy-loss spectroscopy (EELS) combined with the analysis method of non-negative matrix factorization (NMF), which is an algorithm that can accomplish the decomposition of high-dimensional data, especially the data which must be positive to implement its physical significance. NMF algorithms of different forms are adopted in this paper to tackle the problem. It is shown that two types of iteration methods, fast hierarchical alternating least squares (Fast-HALS) and spatial orthogonal (SO)-HALS provide decent NMF results on EELS datasets of lithium element. In particular, the low-loss and the core-loss regions of the EELS data are combined together in the process of NMF analysis, enabling better distinction of different chemical states. The above algorithms are recommended for the purpose of analyzing the EELS datasets containing different chemical states of lithium.

Disposal of the Lithium-ion Current Sources by Mechanochemical Degradation

Lithium-ion current sources in a ball mill and comparing this energy with the binding energies of lithium ions with various metals of a cathode material for mechanochemical destruction. The binding energies of lithium ions in various lithium-containing compounds are shown. The calculation of the technological and design parameters of the ball mill to determine the magnitude of the energy of the collision of the grinding bodies and the grinded material. The graphic dependences are given, allowing to reveal the influence of the ratio of the diameter of the balls and their number on the process of mechanochemical destruction.

Recycling Lithium-containing Compounds from Spent Current Sources

The work is devoted to the development of an assessment of existing methods of utilization of lithium chemical current sources. Modern types of lithium-ion current sources are analyzed. It is shown that the cathode and electrolyte materials are most valuable for the process of separating commercial lithium. A modern technological disposal scheme is proposed, where mechanical activation processes are used using ball mills and baromembrane technologies (ultrafiltration and reverse osmosis). The results of experimental studies on the pilot plant.

Phase diagram, thermodynamic investigations, and modelling of systems relevant to lithium-ion batteries

AbstractThis article reports on two consecutive joint projects titled “Experimental Thermodynamics and Phase Relations of New Electrode Materials for Lithium-Ion Batteries”, which were performed in the framework of the WenDeLIB 1473 priority program “Materials with new Design for Lithium Ion Batteries”. Hundreds of samples were synthesized using experimental techniques specifically developed to deal with highly reactive lithium and lithium-containing compounds to generate electrochemical, phase diagram and crystal structure data in the Cu–Li, Li–Sn, Li–Sb, Cu–Li–Sn, Cu–Li–Sb and selected oxide systems. The thermochemical and phase diagram data were subsequently used to develop self-consistent thermodynamic descriptions of several binary systems. In the present contribution, the experimental techniques, working procedures, results and their relevance to the development of new electrode materials for lithium ion batteries are discussed and summarized. The collaboration between the three groups has resulted in more than fifteen (15) published articles during the six-year funding period.

COMPARISON OF EXTRACTION METHODS OF LITHIUM AND ITS COMPOUNDS FROM NATURAL RAW MATERIALS

The paper deals with lithium (and its compounds) which is one of the promising materials used in hydrogen energy. Its individual and complex hydrides are used for storing and transporting hydrogen in hydrogen power plants. The paper compares the different methods of lithium extraction from natural raw materials. The main industrial techniques of processing spodumene and other lithium minerals are considered. Since the volumes of these mineral deposits in the world are limited, hydro-mineral raw materials gradually become the main source of lithium. The paper focuses on the analysis of methods for lithium containing hydromineralic raw materials processing. The paper indicates that at the first stage of lithium recovery (the production of its concentrates) there are the most commonly used the galurgical methods of concentrating and isolating lithium from natural brines. However, these methods are only applicable to rich natural lithium brines. Another method (the method of its deposition in the form of sparingly soluble compounds) is danger from the ecological point of view due to the large impact on these brines, and the problems of their further utilization. The sorption methods of lithium extraction, especially from poor in composition of natural and technological solutions, are more promising. In view of complexity of the salt composition of hydro-mineral raw materials, the use of highly selective inorganic ion-exchange materials is the most promising method for recovery of lithium too. In order to complete the general picture of lithium production, the paper analyzes the modern methods for obtaining metallic lithium and various lithium-containing compounds. Moreover, the paper describes the methods of reprocessing lithium carbonate into other compounds, as well as methods for obtaining lithium hydroxide and lithium chloride, and electrochemical and vacuum-thermal methods for obtaining metallic lithium. Furthermore, the methods of lithium refining and the need for processing secondary lithium resources are briefly considered.

Progress in surface coating on LiNi<sub>0.8</sub>Co<sub>0.15</sub>Al<sub>0.05</sub>O<sub>2</sub> cathode materials for lithium-ion batteries

Cathode materials with high energy density and long life are currently the focus in the research and development of advanced lithium-ion batteries. Compared to traditional commercial layered LiCoO2, the nickel-rich cathode material with typical composition of LiNi0.8Co0.15Al0.05O2 (NCA) has attracted intensive interest because of advantages of low cost and high specific capacity (i.e., ~200 mAh/g). However, this promising cathode material suffers from problems, such as severe irreversible capacity loss and poor performance at high temperature due to the mixed cation distribution of Li/Ni and the presence of high-valent Ni on charge that poses structural instability and strong oxidizing ability. There are generally two strategies to address the issues, namely, cation doping and the more extensively employed surface coating. In this article, we review recent progress made in surface coating of NCA cathode materials. Currently, the materials used for coating NCA mainly include carbonaceous materials (e.g., graphene), oxides and composite oxides (e.g., SiO2, CeO2, TiO2, and Li2O-2B2O3), fluorides (AlF3), lithium-containing compounds (e.g., LiCoO2), phosphates (e.g., AlPO4 and Co3(PO4)2) and polymers (e.g., polyaniline). The surface-coated NCA shows better cycling performance as compared to the raw material. The effect of coating on electrode properties varies among different coated materials. The coating of oxides/fluorides/phosphates reduces the corrosion of electrolyte on the electrode and suppresses the side reaction between the electrolyte and the electrode, giving rise to better capacity retention. Carbonaceous materials and composite oxides exert similar protective effect and help to improve the electrical and ionic conductivity. Some stable lithium-containing compounds are coated on NCA to form a core-shell structure, facilitating both Li+ insertion/delithiation and electron conduction with reduced electrode polarization and enhanced electrode stability. The coating methods also affect the electrode performance. Coating can be achieved through mechanical or chemical ways. The former is to mechanically mix the coating material and the raw NCA material by stirring or milling. Mechanical coating is simple in processing but is energy consuming and may incur structural/morphological break. Chemical coating is to generate in situ the coated material on the surface of raw material via chemical reactions. Complicated procedures are often required to make the coating layer uniformly distributed on target materials. As the coated materials are generally electrochemically inactive, their amount should be kept minimized to reduce expense of available capacity. Additionally, the type of coated materials and the thickness of coating layer should be optimized to make full advantage of coating. As a result of surface modification, the cyclability and thermal stability of NCA cathode materials can be greatly improved as compared to the pristine uncoated electrode.

ChemInform Abstract: Soft Mechanochemical Synthesis of Materials for Lithium‐Ion Batteries: Principles and Applications

AbstractReview: 46 refs.

Stabilizing role of lithium in structures of complex oxide compounds as an instrument for crystal chemical design

Crystal chemical features of some complex oxide lithium-containing compounds, in particular, triple molybdates, are considered to reveal the structure-forming significance of lithium. Its role is actually reduced to the realization of structures with a simpler composition through the introduction and heterovalent substitution. Specific stabilization ways can be very diverse owing to the high adaptability of lithium atoms in the structure. They can reside in the same crystallographic positions together with alkali metals (including potassium), medium-size, and even larger two- and three-charged cations and also to occupy the cavities. Such an adaptability and a low charge of the Li+ ion with its appropriate distribution in the structure allow the elimination of imbalance in cation charges and sizes of their coordination polyhedra. They also provide the filling of available vacancies, which produces a significant stabilizing effect. The stabilization of the structures with other cations or their combinations is exemplified. Attention is drawn to the relation between the structural and thermal stabilization. It is concluded that the crystal chemical stabilizing features of lithium and other cations can be used as an instrument for the design of novel compounds and materials.

Structure and Ionic‐Transport Properties of Lithium‐Containing Garnets Li3Ln3Te2O12 (Ln: Y, Pr, Nd, Sm—Lu).

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.

Structure and Ionic-Transport Properties of Lithium-Containing Garnets Li3Ln3Te2O12 (Ln = Y, Pr, Nd, Sm−Lu)

Lithium-containing compounds of the formula Li3Ln3Te2O12 (Ln = Y, Pr, Nd, Sm−Lu) have been prepared by solid-state ceramic methods at temperatures up to 900 °C. Rietveld refinement against X-ray and neutron powder diffraction data show that these phases adopt the garnet structure (space group Ia3̄d) with lattice parameters in the range 12.15970(14) Å (Li3Lu3Te2O12) to 12.61596(7) Å (Li3Pr3Te2O12). The Ln3+ and Te6+ cations occupy the 8-fold and octahedrally coordinated sites, and Li+ is accommodated exclusively in the tetrahedral sites commonly occupied in the garnet structure. Neutron diffraction data collected from Li3Nd3Te2O12 at 300 and 600 °C show that the lithium coordination does not change over this temperature range. Impedance spectroscopy measurements indicate that Li3Nd3Te2O12 shows minimal Li+ mobility with an activation energy of 1.22(15) eV, resulting in a maximum observed conductivity of σ ≈ 1 × 10-5 S cm-1 at 600 °C.

Study of Li insertion mechanisms in transition metal antimony compounds as negative electrodes for Li-ion battery

MSb (M = Ni, Co, Fe, Mn) alloys with a NiAs type structure were synthesized by ceramic route and evaluate as a negative electrode material for rechargeable lithium batteries. Electrochemical tests demonstrated that initial charge and discharge capacities of this materials were ca. 390 and 330 mAh g −1, respectively. Ex situ XRD of MnSb electrodes showed that LiMnSb and Li 3Sb were successively formed during lithium insertion. The 121Sb Mössbauer spectra show that the insertion mechanism during discharge involves the formation of several lithium-containing compounds such as LiMnSb, Li 3Sb with manganese extrusion. During the subsequent charge a more complex mechanism occurs involving MnSb, modified LiMnSb alloy and metallic Sb formation.

Anode behaviors of magnesium–antimony intermetallic compound for lithium secondary battery

Abstract Mg 3 Sb 2 with a structure of A-type rare earth oxide (hexagonal) was synthesized by mechanical alloying (MA) and evaluated as a negative electrode material for rechargeable lithium batteries. Electrochemical tests demonstrated that the initial charge and discharge capacities of Mg 3 Sb 2 were ca. 850 and 600 mA h g −1 , respectively. Ex situ XRD of the Mg 3 Sb 2 electrodes showed that several lithium-containing compounds such as LiMgSb and Li 3 Sb were successively formed during the insertion of lithium into Mg 3 Sb 2 . As to LiMgSb synthesized by MA-method, the electrode performance was also investigated; it showed an excellent reversibility at the first cycle and a rechargeable capacity of ca. 200 mA h g −1 after the fourth cycle. The cycle life performance of LiMgSb electrode was significantly enhanced in comparison with that of Mg 3 Sb 2 .

Electrochemical Intercalation of Lithium into Intermetallic Bismuth Compounds with Indium in Nonaqueous Solutions

Phase conversions and kinetics of electrochemical intercalation of lithium from dimethylformamide solutions of LiCl into bulk electrodes of bismuth, indium and their intermetallic compounds InBi and In2Bi are studied using chronopotentiometry and chronoamperometry methods. The intercalation is controlled by non-steady-state lithium diffusion in the solid electrode. In the lithium–intermetallic compound systems, both components of alloys take part in the formation of compounds with lithium. Considerable volume changes, which occur during the intercalation, may lead to disintegration of lithium-containing phase constituents with a high lithium content. The “extremum” shape of cathodic chronoamperograms may be due successive and/or parallel reactions in which various lithium-containing compounds form. Some of these reactions are limited by solid-phase diffusion, while others involve the formation and diffusion-controlled growth of three-dimensional nuclei of a new phase.

Response of Hydrocarbon Fuels to Lithium-Containing Antiknock Compounds

Organolithium compounds were investigated as chemical controllers of hydrocarbon combustion. The response of individual hydrocarbons of different classes, reference mixtures, naphtha cuts, and base compositions of commercial gasolines was investigated as a function of the concentration of lithium in them. The mechanism of action of lithium-containing antiknock compounds is proposed.

A study of Zn 4Sb 3 as a negative electrode for secondary lithium cells

Antimony zinc alloy, Zn 4Sb 3, was studied as a potential material for negative electrodes of lithium-ion batteries. It was found that the reversible capacity of ball-milled Zn 4Sb 3 in the first cycle reached 507 mA h g −1 and increased up to 580 mA h g −1 when the alloy was ball-milled with about 11.8 wt.% graphite additives. Ex-situ XRD analyses of the pure Zn 4Sb 3 electrodes during cycling showed that several lithium-containing compounds such as LiZnSb, Li 3Sb and LiZn have been formed successively during the insertion of lithium into Zn 4Sb 3. It was found that the ball-milled composite, Zn 4Sb 3/C 7, possesses high initial reversible capacity, small voltage hysteresis and good capacity retention, which make this material an interesting potential electrode for lithium-ion batteries.