Lithiated Cathode Materials Research Articles

Current-Dependent Lithium Metal Microstructure in ‘Anode-Free’ Solid-State Batteries at the Steel|LPSCI Interface

Further improvement of energy densities of state-of-the-art batteries could be achieved with the utilization of lithium metal anodes.1 Due to the reactivity of the alkali metal, the fabrication process needs to be monitored carefully. To circumvent degradation during storage as well as the handling of lithium metal, reservoir-free cells (RFCs) are investigated.2 Using accessible lithium stored within lithiated cathode materials, the lithium anode is formed in a formation step during the first charging cycle. The electrochemical properties of the electrodeposited lithium film are strongly dependent on its microstructure, and can, for example, influence the resoluble amount of lithium during subsequent cycling.3,4 Until now, the microstructure of electrodeposited lithium and how to control it is elusive.To observe and characterize the microstructure of electrodeposited lithium at the stainless steel|LPSCl interface, a combination of electrochemical impedance spectroscopy, focused ion beam and scanning electron microscopy as well as electron backscatter diffraction was used. With this setup, the correlation between deposition current density and resulting microstructure of the lithium film was investigated. For higher current densities, a twenty times smaller grain size was observed, while the grain density showed a twelvefold increase, which could have a major influence on the subsequent dissolution of lithium. Furthermore, the microstructural evolution during prolonged lithium deposition was investigated.1 J. Janek and W. G. Zeier, Nat. Energy, 2016, 1, 16141.2 M. J. Wang, E. Carmona, A. Gupta, P. Albertus and J. Sakamoto, Nat Commun., 2020, 11, 1–9.3 S. E. Sandoval and M. T. McDowell, Matter, 2023, 6, 2101–2102.4 D. K. Singh, T. Fuchs, C. Krempaszky, B. Mogwitz, S. Burkhardt, F. H. Richter and J. Janek, Adv. Funct. Mater., 2023, 33, 2211067.

Enhanced performance of lithiated cathode materials of LiCo 0 . 6 X 0 . 4 O 2 (X = Mn, Sr, Zn) for proton‐conducting solid oxide fuel cell applications

Enhanced performance of lithiated cathode materials of <scp> LiCo ₀ </scp> _. <scp> ₆ X ₀ </scp> _. <scp> ₄ O ₂ </scp> (X = Mn, Sr, Zn) for proton‐conducting solid oxide fuel cell applications

A Novel Approach for Synthesis of Nickel-Rich Layered Oxide Cathode Materials with Tailored Morphology and Their Electrochemical Performance

The improvement in energy density of lithium ion batteries (LIBs) is primarily focused on the increase of the specific capacity of active materials and the cell voltage.[1] Transition metal (TM) oxide-based cathodes materials reach a high specific capacity through the optimization of the chemical composition with a higher Ni content and can be cycled up to 4.6 V.[2] However, the electrochemical performance of Ni-rich cathode materials depends strongly on their physical properties such as particle size, specific surface area or surface characteristics. The poor rate capability and capacity retention as well as the high first cycle irreversible capacity loss (ICL) and the low volumetric energy density of electrodes have to be improved by specific design of the particle shape. A spherical morphology with a narrow size distribution is the preferred particle shape and can only be synthesized during the co-precipitation of TM-hydroxides or -carbonates by a continuously stirred tank reactor (CSTR). Additionally, the CSTR-process allows a further improvement of the cathode materials during the synthesis of core-shell and full concentration-gradient particles.[2] In this work, the design and the operating principle of a novel Couette-Taylor-Flow-Reactor (CTFR) is evaluated regarding the synthesis of spherical shaped Ni-rich TM-precursors. The CTFR offers a continuous process and is constructed by two co‐axial arranged cylinders with a small gap and a low working volume. The rotational motion of the inner cylinder induces a turbulent Taylor‐vortex flow. Above the suitable Taylor number (Ta), a periodic and stable turbulent fluid motion is formed, which increases the fluid shear and the local concentration of educts and promotes the agglomeration of precipitates to uniform spherical particles with narrow particle size distribution.[3] Based on the co-precipitation of Ni-rich TM-precursors by a continuous CTFR, the influence of the reaction conditions on the properties of TM-precursor is investigated. The rotational speed, residence time, temperature and pH-value were varied in a broad range. The growth behavior of the particles, regarding the morphology, particle size distribution, tap density and chemical composition of TM-precursors as well as for lithiated cathode materials are investigated. The electrochemical properties of the corresponding cathode materials with their unique particle morphology in dependence of the co-precipitation conditions are comprehensively evaluated for finding the optimal synthesis conditions. [1] J. Betz, G. Bieker, P. Meister, T. Placke, M. Winter, R. Schmuch, Adv. Energy Mater. 2018, 1803170/1-18.[2] H. Li, P. Zhou, F. Liu, H. Li F. Cheng, J. Chen, Chem. Sci, DOI: 10.1039/c8sc03385d.[3] J.-M. Kim, S.-M. Chang, J.-H. Chang, W.-S- Kim, Colloids and Surfaces A: Physicochem. Eng. Aspects (2011) 384, 31-39.

(Keynote) Redox-Active Organic Species for Rechargeable Batteries, and Beyond!

Our entry into the Fourth industrial revolution since the turn of the century is set to revolutionize our daily life notably with the blooming of digital technologies such as communications, artificial intelligence, technologies related to the Internet of Things (IoT), 3-D printing or nano/bio-technologies. It is however hoped this new paradigm shift will integrate sustainable development goals and actions to address the critical damage caused by the previous industrial revolutions especially the threat of global warming. We have to be particularly aware there remains the urgent need for cleaner energy technologies which calls for a radical change in the energy mix to favour renewable energy and environmentally responsible energy storage solutions. To date, commercial batteries exclusively include inorganic electrode materials notably 3d transition-metals which are scarce, expensive and energy-greedy. In contrast, organic materials enable access to low cost and possibly greener compounds because composed of naturally abundant elements (i.e., C, H, O, N or S) moreover they are easier to recycle. In addition, they offer high structural designability through the well-established principles of organic chemistry and notably access to both n- and p-type electrochemical storage mechanisms making various cell or electrode configurations possible (Figure 1). In 10 years, tremendous progress has been made to promote organic compounds in various rechargeable storage devices giving rise to nearly 15 published review articles especially for applications in non-aqueous (metallic) Li or Na-based batteries. However, several improvements are needed to further promote insertion organic electrode materials. For instance, only few studies have been reported in the literature regarding the assembly of full Li-ion organic cells while the literature is quite abundant in terms of Li metal-organic batteries; the main difficulty being to successfully synthesize robust lithiated cathode materials. This contribution aims at reporting recent electrochemical data obtained with crystallized organic materials and explaining how it is possible to tune the electrochemical activity towards higher voltages depending on the molecular assembly and its electrostatic environment in Li enolate-based organic cathodes. In addition, a specific electrochemical study using soluble redox-active organic species will be reported providing to the Li battery community a supplementary proof concerning the high reactivity of the most popular supporting salt (i.e., LiPF6) versus any labile proton potentially present in a battery electrolyte. Figure 1

An air-stable lithiated cathode material based on a 1,4-benzenedisulfonate backbone for organic Li-ion batteries

To meet current market demands as well as emerging environmental concerns there is a need to develop less polluting battery technologies.

Understanding the SEI Formation at Pristine Li‐Ion Cathodes: Chemisorption and Reaction of DEC on LiCoO2 Surfaces Studied by a Combined SXPS/HREELS Approach

AbstractReactions and solid electrolyte interface (SEI) formation at electrode–electrolyte interfaces are crucial for the stability and performance of Li‐ion batteries, but are still not fully understood on a fundamental level. For improving battery properties, a detailed understanding of these degradation processes is needed. In this contribution, the interface formation between a thin film LiCoO2 cathode material and diethyl carbonate (DEC) as typical battery electrolyte solvent is presented. A surface‐science approach is used performing a stepwise adsorption of DEC onto LiCoO2 at low temperatures. The interface is studied after each step by synchrotron‐based X‐ray photoemission spectroscopy (SXPS) and high‐resolution electron energy loss spectroscopy. The results demonstrate that the decomposition of carbonate solvents in contact with fully lithiated cathode materials as observed in adsorption experiments is complex, including the reduction of solvent, subsequent decomposition reactions, and also catalytic effects. In the present case, lithium ethyl carbonate, lithium ethoxide, and lithium oxides are assigned as reaction products. The spectra provide indications for partial electron transfer coupled to covalent interaction involving surface oxygen O2p orbital and DEC lowest unoccupied molecular orbital (LUMO) states.

Characterization on the exothermic behaviors of cathode materials reacted with ethylene carbonate in lithium-ion battery studied by differential scanning calorimeter (DSC)

Seven lithiated and delithiated cathode materials mixed with ethylene carbonate (EC) were studied by differential scanning calorimeter (DSC) for measuring exothermic phenomena. Effects of lithiated and delithiated cathode materials with EC upon the exothermic behaviors were verified and compared. Lithiated cathode materials keep higher stability than delithiated ones. LiCoO2, LiNi0.8Co0.2O2, LiNi1/3Mn1/3Co1/3O2 (NMC333), and LiNi0.5Mn0.3Co0.2O2 (NMC532) react with EC all exhibiting significant exothermic peaks at about (370±20)°C owing to the common component of Co ion. In the delithiated NMC333, NMC532 and LiNi0.8Co0.2O2, effects of Ni ion manifestly resulted in the lower onset temperatures and exothermic peaks than those of lithiated cathode materials. Especially, the onset temperature of delithiated LixNi0.5Mn0.3Co0.2O2 with EC appears at around 98.9°C. EC with delithiated LixCoO2 displaying four peaks has been novel discovered and associated with a strong peak occurred at about 222.2°C. Impacts of Ni, Mn, and Co ions on the thermal stability associated with the structural stability in deliathiated cathode materials under high temperature conditions are discussed.

Stable Lithium Electrodeposition in Liquid and Nanoporous Solid Electrolytes

High energy and safe electrochemical storage are critical components in multiple emerging fields of technology where portability is a requirement for performance and large-scale deployment. From advanced robotics, autonomous aircraft, to hybrid electric vehicles, the number of technologies demanding advanced electrochemical storage solutions is rising. The rechargeable lithium ion battery (LIB) has received considerable attention because of its high operating voltages, low internal resistance and minimal memory effects. Unfortunately LIBs are currently operating close to their theoretical performance limits due to the relatively low capacity of the anode LiC6 and the lithiated cathode materials (LiCoO2 and LiFePO4) in widespread use. It has long been understood that a rechargeable lithium metal battery (LMB), which eschewed the use of a carbon host at the anode can lead to as much as a ten-fold improvement in anode storage capacity (from 360 mAh g-1 to 3860 mAh g-1) and would open up opportunities for high energy un-lithiated cathode materials such as sulfur and oxygen, among others. Together, these advances would lead to rechargeable batteries with step-change improvements in storage capacity relative to today’s state of the art LIBs.A grand challenge in the field concerns the development of electrolytes, electrode, and battery systems configurations that prevent uneven electrodeposition of lithium and other metal anodes, and thereby eliminate dendrites at the nucleation step. It is understood that without significant breakthroughs in this area, the promise of LMBs, as well as of storage platforms based on more earth abundant metals such as Na and Al metal cannot be realized. Specifically, after repeated cycles of charge and discharge growing metal dendrites can bridge the inter-electrode space, producing internal short circuits in the cell. In a volatile electrolyte, ohmic heat generated by these shorts may lead to thermal runaway and catastrophic cell failure, which places obvious safety and performance limitations on the cells. The ohmic heat generated during a short-circuit may also locally melt dendrites to create regions of “orphaned” or electrically disconnected metal that results in a steady decrease in storage capacity as a battery is cycled. Lithium-ion batteries (LiB) are designed to remove these risks by hosting the lithium in a conductive carbon host at the anode. However, the small potential difference that separates lithium insertion into versus plating onto carbon can potentially lead to similar failure modes in an overcharged or too quickly charged LiB. Thus, the need for materials that prevent non-uniform electrodeposition of metals such as Li is also implicit in new fast charging LIB technology targeted for electric-drive vehicles. We have investigated electrodeposition of lithium in simple liquid electrolytes such as propylene carbonate, ethylene carbonate and diethyl carbonate, and in nanoporous solids infused with liquid electrolytes. We find that simple liquid electrolytes reinforced with LiXA blends exhibit stable long-term cycling at room temperature, often with no signs of deposition instabilities over hundreds of cycles of charge and discharge and thousands of operating hours. We rationalize these observations with the help of surface energy data for the electrolyte/lithium interface and impedance analysis of the interface during different stages of cell operation. Our findings provide support for an important recent theoretical prediction that the surface mobility of lithium is significantly enhanced in the presence of LiXA.

Synthesis and characterization of manganese-, nickel-, and cobalt-containing carbonate precursors for high capacity Li-ion battery cathodes

Mn-rich transition metal (Mn, Ni, Co) carbonate precursor was precipitated as the precursor for Li- and Mn-enriched composite material used as advanced cathode for lithium-ion battery. The pH zone that favors carbonate precipitation reactions for transition metals (Co, Ni, Mn) was predicted by taking into account the chemical equilibriums between metal elements Me (Co, Ni, Mn) and ammonia bicarbonate. The physical properties of the precursor and the final lithiated cathode material were characterized in detail, and the electrochemical properties of the prepared Li1.2Ni0.12Co0.12Mn0.56O2 powder were evaluated. The study aids in understanding the precipitation and yields an optimal precipitation condition for the system.

Voltage Gain in Lithiated Enolate-Based Organic Cathode Materials by Isomeric Effect

Li-ion batteries (LIBs) appear nowadays as flagship technology able to power an increasing range of applications starting from small portable electronic devices to advanced electric vehicles. Over the past two decades, the discoveries of new metal-based host structures, together with substantial technical developments, have considerably improved their electrochemical performance, particularly in terms of energy density. To further promote electrochemical storage systems while limiting the demand on metal-based raw materials, a possible parallel research to inorganic-based batteries consists in developing efficient and low-polluting organic electrode materials. For a long time, this class of redox-active materials has been disregarded mainly due to stability issues but, in recent years, progress has been made demonstrating that organics undeniably exhibit considerable assets. On the basis of our ongoing research aiming at elaborating lithiated organic cathode materials, we report herein on a chemical approach that takes advantage of the positive potential shift when switching from para to ortho-position in the dihydroxyterephthaloyl system. In practice, dilithium (2,3-dilithium-oxy)-terephthalate compound (Li4C8H2O6) was first produced through an eco-friendly synthesis scheme based on CO2 sequestration, then characterized, and finally tested electrochemically as lithiated cathode material vs. Li. This new organic salt shows promising electrochemical performance, notably fast kinetics, good cycling stability and above all an average operating potential of 2.85 V vs. Li(+)/Li(0) (i.e., +300 mV in comparison with its para-regioisomer), verifying the relevance of the followed strategy.

Thermal instabilities of organic carbonates with discharged cathode materials in lithium-ion batteries

Thermal instability of lithiated cathode materials with organic carbonate were investigated using DSC. Lithium transition metal oxides of LiFePO4, LiMn2O4, and LiCoO2 were mixed with diethyl carbonate, dimethyl carbonate, ethylene carbonate, ethyl methyl carbonate, and propylene carbonate then dynamically screened to about 500 °C. Curves were acquired and analyzed to determine exothermic onset temperatures and reaction enthalpies. These data for assessing the thermal hazards of lithium-ion batteries under discharged conditions were compared to those data published in the literature.

A green Li–organic battery working as a fuel cell in case of emergency

The routine access to electricity always means a drastic change in terms of quality of life making it easier and safer. Consequently, the global electric demand both on and off-the-grid is growing and calls for ongoing innovation to promote reliable, clean and safe power supplies. In this context, the development of new chemistries for batteries and fuel cells could play a critical role. From our prospects aiming at fostering the concept of sustainable organic batteries, we report in this article on the peculiar properties of dilithium (2,5-dilithium-oxy)-terephthalate salt, a novel redox-active material. Based on an oriented retrosynthetic analysis, we have succeeded in elaborating this organic electrode material through an original and low-polluting synthesis scheme, which includes both chemical and biochemical CO2 sequestration in conjunction with a closed-loop solution for recycling products. Beyond its remarkable electrochemical performance vs. Li, especially as a lithiated cathode material, this compound behaves also like an oxygen scavenger. This dual electrochemical/chemical reactivity makes the self-recharging of a Li cell based on this organic salt possible by opening it to air ensuring an electrical power reserve when a conventional electrical recharge is not possible. In such a case, the pristine rechargeable Li–organic battery operates as a sort of “Li/O2 fuel cell”.

Growth mechanism of Ni0.3Mn0.7CO3 precursor for high capacity Li-ion battery cathodes

Transition metal carbonate (Ni0.3Mn0.7CO3) was co-precipitated as the precursor for Li- and Mn-enriched composite materials used as advanced cathodes for lithium-ion batteries. The optimal pH range for synthesis of Ni0.3Mn0.7CO3 in a continuous stirred tank reactor (CSTR) at the pilot scale was predicted by taking into account the chemical equilibriums between the products and reactants. The nucleation and growth of precursor particles were investigated during the CSTR process by monitoring particle size distributions, particle morphologies, chemical compositions, and structures with time. It was found that in the early stage of co-precipitation both the particle size distribution and the chemical composition were not homogeneous; a lead time of about 5 hours under our experiment conditions was necessary to achieve the uniformity in particle shape and chemical composition. The latter was not altered during extended times of co-precipitation; however, a continuous growth of particles resulted in relatively large particles (D50 > 30 μm). The electrochemical performance of the final lithiated cathode materials is reported.

Direct thermal reaction for preparation of lithiated cathode materials without any artificial mixing procedures

Lithiated cathode materials are economically prepared using eutectic self-mixing method, spontaneous mixing of molten acetates and direct thermal reaction, without pulverization, grinding, agglomeration, morphology controlling, particle size controlling, and even any artificial stirring. When the chemical compounds with low melting point, such as lithium acetate and manganese acetate, are exposed to their eutectic temperature, they can be fluid substances by themselves without any solvents and spontaneous mixing. Using this method, we succeed in obtaining various lithiated cathode materials by just simple heat treatment. The discharge capacities of 149.5, 162.2, and 112.0 mA h/g for LiCoO 2, LiNi 0.8Co 0.2O 2, and LiMn 2O 4, respectively, prepared by this method demonstrate that the prepared materials are quite prospective as cathode materials for lithium rechargeable battery.

Ab Initio Calculations and Structural Stability of Boron-Doped Sodium Manganese Oxide

The structural stability of where has been studied using first-principles density-functional theory with pseudopotentials and plane-wave basis (VASP). In addition, the structural stability of the oxides with 75% vacancies of Na ions for each concentration of B has been investigated. Results of the simulation show that the monoclinic phase of these oxides is thermodynamically stable for all the B concentrations studied. Moreover, substitution of a larger amount of boron results in a higher energy difference between the monoclinic phase and its nearest concurrent orthorhombic phase. Furthermore, deintercalation of Na ions from the parent oxide has shown that the monoclinic phase is stable and does not undergo any structural transformation to the spinel phase, which could be expected with substantial removal of Na ions. The energy difference between the monoclinic and spinel crystal structures increases with increasing amounts of boron and reaches a value of 13.0 kJ/mol for 37.5% B. Based on our studies, it appears that with an optimum amount of B can be used as a potential parent cathode for the synthesis of a lithiated cathode material by ion-exchange following the chimie douce reaction. © 2003 The Electrochemical Society. All rights reserved.