Lithium Manganese Oxide Research Articles

The Role of Surface Coatings on the Strain Evolution in Li-Ion Cathode Electrodes during Electrochemical Cycling

Rechargeable Li-ion batteries (LIBs) have been successfully commercialized for portable electronics in the last two decades. Although there has been a great interest to use LIBs in more demanding applications such as electric vehicles, adoption of LIBs has been hindered by capacity loss and poor performance. The current stage of the cathode performance is a limiting factor for the development of higher performance LIBs. Cathode electrodes suffer from significant capacity fade with cycling due to continuous volumetric changes, unstable cathode-electrolyte interface and active material dissolution. Lithium intercalation induces considerable volumetric changes in the electrode and even small strain can cause particle fractures in brittle cathode materials. Surface modification of the cathode electrodes has been used to improve the capacity retention and cycling stability of the electrodes at higher charge/discharge rates by minimizing active material dissolution and stabilizing the electrode-electrolyte surface layer. Although various surface modification techniques were utilized to improve the performance of the electrodes, the underlying mechanism of surface modification has not been elucidated yet. In this work, we investigated the role of surface coatings on the strain generation in lithium manganese oxide (LMO) composite electrodes. Full-field strain measurements based on digital image correlation (DIC) is carried out to measure strain evolution in LMO electrodes1. Scalable electrolysis deposition method was performed to coat LMO particles with Au shell2. LMO composite electrodes were fabricated with a composition of 8:1:1 weight ratio of LMO, carboxymethyl cellulose binder and carbon black. Electrodes were cycled with cyclic voltammetry technique at different scan rates (between 10 and 100μV/s). As expected, composite electrodes expanded during delithiation when lithium is inserted into the electrode and contacted during lithiation when lithium is removed. Capacity was calculated to understand relationship between strain evolution with amount of lithium ions in the electrode at a given scan rate. Interestingly, The LMO electrode without coating undergoes larger strain generation at higher scan rates compared to LMO electrode with surface coatings. Volumetric expansion of LMO (without coating) electrode changes dramatically depending on scan rate whereas strain evolution in the gold-coated LMO electrode is primarily function of capacity, regardless of scan rate. The role of the surface coatings on the mechanical and electrochemical performance of the LMO electrodes will be discussed. References Ö. Ö. Çapraz, S. Rajput, S. White, and N. R. Sottos, Exp Mech, 15, 1182–11 (2018).J. L. Esbenshade, M. D. Fox, and A. A. Gewirth, J. Electrochem. Soc., 162 (1), A26 (2015). Acknowledgement This work was supported as part of the Center for Electrochemical Energy Science (CEES), an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences.”

In Situ Chemo-Mechanical Responses of Lithium Iron Phosphate Electrodes during Electrochemical Cycling

Rechargeable Li-ion batteries (LIBs) have been successfully commercialized for portable electronics in the last two decades. Although there has been a great interest to use LIBs in more demanding applications such as electric vehicles, adoption of LIBs has been hindered by capacity loss and poor performance. The current stage of the cathode performance is a limiting factor for the development of higher performance LIBs. Lithium intercalation induces considerable volumetric changes with associated stress generation in the electrode. Even small strain can cause particle fractures in brittle cathode materials. The formation of a fracture particles leads to the capacity fade and limits the lifetime of batteries. To investigate chemo-mechanical response of the cathodes, we previously calculated electrochemical stiffness changes cathodes by coordinating in situ stress and strain measurements1. The electrochemical stiffness response of lithium manganese oxide revealed that the underlying mechanisms governing stress and strain are intrinsically different. In this study, our objective is to evaluate chemo-mechanical responses of lithium iron phosphate (LFP) cathode. In situ stress measurements were carried out with the beam curvature method whereas digital image correlation (DIC) is utilized to measure in situ strain generation. Electrodes are constrained on the cantilever for stress measurement, whereas free-standing electrodes were fabricated for strain measurements. LFP electrodes were fabricated with a composition of 8:1:1 weight ratio of LFP, carboxymethyl cellulose binder and carbon black. Electrodes are cycled with cyclic voltammetry technique at different scan rates (between 10 and 250μV/s) in various electrolytes. Stress and strain derivatives are calculated with respect to applied potential. Derivatives present crucial information to probe potential-dependent surface stress evolutions and structural changes in the electrode. As expected, strain derivatives are well-correlated with the changes in the crystal structure during delithiation and lithiation. Interestingly, stress derivatives reveal that electrolyte solution has a role on the evolution of surface stress. Changes in stress and strain during electrochemical cycling reveal underlying mechanisms governing chemo-mechanical responses in the LFP electrode. References 1- Ö. Ö. Çapraz, K. L. Bassett, A. A. Gewirth, and N. R. Sottos, Adv. Energy Mater., 1601778–7 (2017). Acknowledgement This work was supported as part of the Center for Electrochemical Energy Science (CEES), an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences.”

Fe3O4-doped lithium ion-sieves for lithium adsorption and magnetic separation

Spinel lithium manganese oxide ion-sieve is considered the most promising adsorbents to extract lithium from brine. Here, we report a Fe3O4-doped magnetic lithium ion-sieve prepared by a facile hydrothermal method. The Fe3O4-doped lithium manganese oxide (LMO/FO) was first synthesized as the magnetic ion-sieve precursor. The chemical and morphological properties of LMO/FO were investigated by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results showed that Fe3O4 was uniformly dispersed in the precursor. Doping Fe3O4 into LMO led to the increase of the average valence for Mn in the precursor from +3.48 to +3.53, which helps improve its structural stability. The equilibrium adsorption capacity of acid-treated LMO/FO (i.e. HMO/FO) was 29.33 mg/g which was greater than that of the undoped (i.e. HMO). Moreover, the adsorption behavior of the both ion-sieves well fitted with pseudo-second-order kinetic model. In 0.05 mol/L HCl solution, the desorption equilibrium could be achieved after 30 min. The dissolution loss of manganese and iron were 6.22% and 4.14%, respectively. The saturation magnetization value (Ms) of LMO/FO is 2.5 emu/g and the solid-liquid separation can be achieved by a magnet. In addition, the magnetic ion-sieve demonstrated excellent adsorption selectivity to Li+ in a mixed solution containing Li+, Na+, K+, Mg2+ and Ca2+.

Modeling of separator failure in lithium-ion pouch cells under compression

The failure of the separator membrane by rupture or thermal runaway is the prime cause of concern for the lithium battery system. In this work, we model the mechanical behavior and ionic conductance of the separator membrane under compression and its influence on the lithium cell thermal performance. The separator membrane is modeled as an open-cell foam to correlate the mechanical deformation under compressive loads and ionic conductivity. Predicted correlation between mechanical deformation and ionic conductivity is compared with experimental reports of membrane performance. Next, the validated model is used to simulate the thermal performance of lithium-ion pouch cells. Thermal response is predicted for a number of different pouch cell configurations with graphite (C) as anode; cathode chosen from lithium manganese oxide (LMO), lithium cobalt oxide (LCO) or lithium ferrous phosphate (LFP); and separator membrane chosen from monolayer polypropylene (PP), monolayer polyethylene (PE), trilayer, non-woven or ceramic-coated. The thermal response is used to predict the average cell temperature under an applied compressive load. Design maps that plot the maximum cell temperature over a range of applied load for different rates of charging and cooling conditions are prepared and used to identify the design conditions leading to separator meltdown and thermal runaway.

Simultaneous Optimization of Adsorption Capacity and Stability of Hydrothermally Synthesized Spinel Ion Sieve Composite Adsorbents for Selective Removal of Lithium from Aqueous Solutions

The main aim of this paper was synthesis of spinel type lithium manganese oxide adsorbent with high adsorption capacity and stability for selective removal of lithium ion. In contrast with the prev...

A new class of lithium-ion battery using sulfurized carbon anode from polyacrylonitrile and lithium manganese oxide cathode

Lithium metal has been considered as a potential anode material than those currently used to increase the energy density of lithium ion battery. However, lithium metal anodes suffer from destructive dendrite formation, which causes safety concerns. Anodes with high capacity and safe handling are needed. The sulfurized carbon anode from polyacrylonitrile (S-C(PAN)) composite has been used as a cathode in lithium sulfur batteries. Instead, when the S-C(PAN) is used as an anode and paired with LMO, the full cell delivers an energy density of 185 Wh kg−1(S-C(PAN)+LMO) at 1 C within the voltage range from 1 to 3.2 V. The full cell (S-C(PAN)||LMO) is characterized by a reversible discharge capacity of 1378 mAh g−1S and 868 mAh g−1S at 0.1 C and 2 C, respectively. At 1 C, a retention capacity of 807 mAh g−1S is achieved at the 400th cycle with an average decay rate of 0.7 mAh g−1S*cycle−1 and average coulombic efficiency of 99.5%. Interfacial chemistry of S-C(PAN) anode is particularly investigated and S-C(PAN) is demonstrated as one interesting anode material, alternative to lithium metal, due to its high theoretical capacity of sulfur (1675 mAh g−1), environmental friendliness, low cost, and high energy density.

Improved design of highly efficient microsized lithium-ion batteries for stretchable electronics

We introduce a stretchable microsized Li-ion battery with a novel design. The battery was fabricated using a facile technique and exhibited high performance. Dry-etching process was utilized to pattern lithium phosphorus oxynitride for avoiding the use of a photoresist developer (photolithography), which can damage the amorphous lithium manganese oxide (LiMn2O4 (LMO)) cathode. This allowed us to fabricate the current collectors and electrodes away from the main body of the microsized battery (a parallel structure rather than a stacked, i.e. perpendicular structure). An enhanced capacity of ~150 mAh g−1 was achieved using the parallel device structure at a charge–discharge average potential of 3.7 V; in comparison, the performance of a device with a stacked structure was significantly inferior. The microsized batteries were utilized to illuminate a white inorganic light-emitting diode with a turn-on voltage of ~2.5 V. The fabricated devices with the stacked structure were transferred to a mechanically prestrained (~22.5%) polydimethylsiloxane polymer via a kinetic transfer process. Upon removal of the prestrain, the shrinkage of the substrate caused buckle formation at the interconnects, and tensile damage to the microsized batteries was circumvented. The simulation (COMSOL) results indicated that most of the strain in the standby form (without applied stretching) was concentrated at the interconnects, preventing significant damage in the main device area. Upon the application of 21% stretching (load), although the parallel structure exhibits slightly higher maximum strain in the islands, the strain distribution was more effectively managed, indicating the potential of the proposed method for various stretchable and bendable optoelectronic applications.

An enhanced electrochemical properties of novel tin based layered Li(Ni–Sn–Mn)O2 cathode material for rechargeable Li-ion batteries

In this work, the synthesis of newly prepared cathode material, Li(NixSnyMnz)O2, which is used as a positive electrode material and is suitable for energy storage and conversion in lithium-ion rechargeable batteries, are taken into account. Indeed the main goal is to replace the conventional cathodes such as lithium cobalt oxide, lithium manganese oxide and lithium iron phosphate in view of achieving higher capacity, long cycle life, and better environmental compatible compounds. The stoichiometric ratio of the Li(Ni0.4Sn0.3Mn0.3)O2 material exhibits better performance, after evaluating with various other ratios and it is prepared via a hydrothermal process using Teflon lined autoclave reactor vessel and followed by calcination technique. Furthermore, the prepared material is subjected to XRD, FE-SEM with EDAX, TEM analysis, and also the electrochemical test has been assessed. It includes electrochemical impedance spectroscopy and electrochemical charge-discharge studies using Li/Li(Ni0.4Sn0.3Mn0.3)O2 coin type half-cell (2032 size) at the 0.1 C rate and the voltage range between 4.3–2.5 V. From the electrochemical studies, it has been found that the first charge-discharge capacity obtained of 192 mAh g−1 and 176 mAh g−1, respectively. Thus, the battery efficiency acquired is 97% and it has been maintained after the 1st cycle with a good cyclability also without huge fading. It may be a suitable positive electrode in the half cell Li-ion rechargeable batteries.

Fabrication of scandium-doped lithium manganese oxide as a high-rate capability cathode material for lithium energy storage

Spinel lithium manganese oxide (LiMn2O4) has been widely used as the commercial cathode material for lithium-ion batteries due to its low cost, environmental benignity as well as high-energy density. Nevertheless, LiMn2O4 electrode suffers from a capacity fading during the cycling process, which can be attributed to the manganese dissolution into the electrolyte solution. In this study, the Sc3+-doped LiMn2-xScxO4 (x = 0, 0.03, 0.06 and 0.09) cathode materials have been designed and fabricated using a high-temperature solid-state approach. Structural characterization using XRD indicates that an appropriate amount of Sc3+-ion doping has no influence on the spinel structure of LiMn2O4 material. Morphological characterizations using SEM and TEM reveal that the Sc3+-ion doping can increase the particle size of LiMn2O4. Compared with the undoped LiMn2O4, the Sc3+-ion doped LiMn2-xScxO4 (x = 0.03, 0.06 and 0.09) electrodes exhibit better cycling stability when used as cathodes for lithium energy storage. Particularly, the obtained LiMn1.94Sc0.06O4 shows a stable cycling performance with only about 12.1% capacity loss over 300 cycles at 10 C.

Controlled approach on spinel lithium manganese oxide as possible cathode for high-performance Li-ion supercapacitors

ABSTRACTEnormous research activities have been accomplished to evolve improved cathode for advanced Li-ion-based devices. In this article, we account the preparation of spinel LiMn2O4 synthesized by microwave irradiation method and investigated the influence of calcination temperature (550–750°C) on its crystallinity, morphology and electrochemical properties. The crystallinity of the samples showed a linear increment with the calcination temperature, and from the structural analysis, the interlinking of the polyhedral subunits with one another was encountered. The electrochemical investigations revealed that the sample calcined at 650°C exhibited a high capacitance of 473.44 F/g in the 3M LiNO3 electrolyte with stable cycling performance. The obtained results suggested the significance of optimum calcination temperature in the effective tailoring of crystallinity, morphology and electrochemical properties of LiMn2O4 nanoparticles.

The polarization characteristics of lithium-ion batteries under cyclic charge and discharge

A high-fidelity electrochemical-thermal coupling was established to study the polarization characteristics of power lithium-ion battery under cycle charge and discharge. The lithium manganese oxide lithium-ion battery was selected to study under cyclic conditions including polarization voltage characteristics, and the polarization internal resistance characteristics of the power lithium-ion battery under cyclic conditions were analyzed via the Hybrid Pulse Power Test (HPPC). The results show that for different working conditions, the polarization voltage difference of the power lithium-ion battery is mainly affected by the change in polarization internal resistance. A higher charge-discharge rate, lower ambient temperatures, and more cycles lead to a greater polarization internal resistance of the battery. Meanwhile, the ohmic polarization internal resistance and the concentration polarization internal resistance of the power lithium-ion battery both exhibit different characteristics under different working condition. In addition, the internal resistance of the ohmic polarization is not affected by the change in current, but it is significantly affected by the change in ambient temperature. Therefore, the ohmic polarization voltage reacts rapidly with changes in the charge/discharge state of the battery; the change of the internal resistance of the concentration polarization is relatively slow.

Comparative life cycle assessment of lithium-ion batteries for electric vehicles addressing capacity fade

Lithium-ion batteries are currently used in electric vehicles (EVs) with many advantages; however, batteries contribute significantly to the life cycle environmental impacts of these vehicles. This article presents a comparative life cycle assessment of two types of batteries – lithium manganese oxide (LiMn2O4) and lithium ion phosphate (LiFePO4) – frequently used in EVs, addressing real-life operational conditions and battery capacity fade. The influence of the location of battery manufacturing and vehicle charging (electricity mix) was also assessed. A life cycle model of batteries in an EV with a service life of 200 000 km (functional unit) was implemented to assess Primary Fossil Energy, Global Warming, Acidification, and Eutrophication impacts. Moreover, the environmental performance of EVs considering both battery types was evaluated. The LiFePO4 battery had better operational performance than the LiMn2O4 one and fewer batteries were needed over the EV service life. Conversely, the life cycle impacts of the LiFePO4 batteries were higher than the LiMn2O4 ones mainly due to higher manufacturing impacts. In countries with a mix based on renewable electricity, the battery production is the most important contributor to impacts, while in countries with electricity mostly from fossil sources, the use phase is the most important. For both battery types and most impact categories, the environmental impacts of EVs were highly dependent on the usage scenario and the electricity mix used for charging.

Hydrothermal synthesis of o-LiMnO2 employing Mn mining residues from Amazon (Brazil) as starting material

In this paper, the Mn mining residues from Amazon Region (Brazil) were proposed as low cost starting materials for synthesis of lithium manganese oxide. Thermal and hydrothermal treatments were used to convert the raw material into o-LiMnO2. The as-synthesized product was analyzed by means of X-ray diffraction (XRD), Infrared spectroscopy (IR), Raman spectroscopy (RS), Thermogravimetry (TG) and Differential thermal analysis (DTA). The results showed that o-LiMnO2 was synthesized at 170 °C for 3 days, having the average particle size (Scherrer equation) around 55 nm. The spectroscopy studies (IR and RS) showed bands at 600 and 613 cm−1. Above 430 °C, o-LiMnO2 converted into LiMn2O4 and LiMnO3.

Dynamic imaging of crystalline defects in lithium-manganese oxide electrodes during electrochemical activation to high voltage

Crystalline defects are commonly generated in lithium-metal-oxide electrodes during cycling of lithium-ion batteries. Their role in electrochemical reactions is not yet fully understood because, until recently, there has not been an effective operando technique to image dynamic processes at the atomic level. In this study, two types of defects were monitored dynamically during delithiation and concomitant oxidation of oxygen ions by using in situ high-resolution transmission electron microscopy supported by density functional theory calculations. One stacking fault with a fault vector b/6[110] and low mobility contributes minimally to oxygen release from the structure. In contrast, dissociated dislocations with Burgers vector of c/2[001] have high gliding and transverse mobility; they lead to the formation, transport and release subsequently of oxygen related species at the surface of the electrode particles. This work advances the scientific understanding of how oxygen participates and the structural response during the activation process at high potentials.

Structural and Electrochemical Analyses on the Transformation of CaFe2O4-Type LiMn2O4 from Spinel-Type LiMn2O4.

Lithium manganese oxides have received much attention as positive electrode materials for lithium-ion batteries. In this study, a post-spinel material, CaFe2O4-type LiMn2O4 (CF-LMO), was synthesized at high pressures above 6 GPa, and its crystal structure and electrochemical properties were examined. CF-LMO exhibits a one-dimensional (1D) conduction pathway for Li ions, which is predicted to be superior to the three-dimensional conduction pathway for these ions. The stoichiometric LiMn2O4 spinel (SP-LMO) was decomposed into three phases of Li2MnO3, MnO2, and Mn2O3 at 600 °C and then started to transform into the CF-LMO structure above 800 °C. The rechargeable capacity (Qrecha) of the sample synthesized at 1000 °C was limited to ∼40 mA h·g–1 in the voltage range between 1.5 and 5.3 V because of the presence of a small amount of Li2MnO3 phase in the sample (=9.1 wt %). In addition, the Li-rich spinels, Li[LixMn2–x]O4 with x = 0.1, 0.2, and 0.333, were also employed for the synthesis of CF-LMO. The sample prepared from x = 0.2 exhibited a Qrecha value exceeding 120 mA h·g–1 with a stable cycling performance, despite the presence of large amounts of the phases Li2MnO3, MnO2, and Mn2O3. Details of the structural transformation from SP-LMO to CF-LMO and the effect of Mn ions on the 1D conduction pathway are discussed.

3D lithium ion battery fabrication via scalable stacked multilayer electrodeposition

This study focuses on the creation of 3D full cell lithium ion batteries via a multilayer stacked electrode approach. The electrodepositon based processes enable individual, deterministic control of all cell dimensions, and thus allow for tunable total energy outputs while maintaining excellent intrinsic performance. Incorporation of electrodeposited nanoporous lithium manganese oxide cathodes and thin film nickel–tin anodes into a vertically interdigitated multilayer cell enables energy densities of up to 193 Wh l−1 and power densities of up to 1233 W l−1. Additionally, the multilayer fabrication increases device areal and volume scalability over multiple orders of magnitude, resulting in total energy outputs of up to 20 mWh and power outputs of 178 mW.

Crystalline structure and electrical conductivity of nickel substituted spinel lithium manganese oxide

Spinel LiMn2O4 is an important Li-ion battery cathode material due to its high-capacity, low toxicity and low cost. The substitution of Ni is a solution to overcome the limitation of the material including Jahn-Teller distortion and dissolution of Mn in electrolytes. In this work, the effects of Ni substitution on the structure and electrical conductivity characteristics of LiNixMn2−xO4 (x = 0, 0.05, 0.1, 0.2) that were synthesized by solid state reaction and sol-gel methods were investigated. X-ray diffraction (XRD) analyses revealed that the Ni substitution decreased the lattice constant and Mn–O distance, but increased the Li–O bond length and 8a tetrahedral volume. Although the Rietveld refinement results showed that the crystalline structure parameters of LiNixMn2−xO4 changed linearly by Ni substitution content which favoured the transportation of lithium ion, the relation of Ni content and electrical conductivities was non-linear. By electrochemical impedance spectroscopy (EIS) analyses, minimum peaks of the electronic and ionic conductivities at the substitution level of 0.05 were observed. The EIS analyses also revealed that the conduction behavior of the materials have dominated by the ionic conductivity, which was several orders higher than the electronic conductivity.

Energy and environmental assessment of a traction lithium-ion battery pack for plug-in hybrid electric vehicles

Traction batteries are a key factor in the environmental sustainability of electric mobility and, therefore, it is necessary to evaluate their environmental performance to allow a comprehensive sustainability assessment of electric mobility. This article presents an environmental assessment of a lithium-ion traction battery for plug-in hybrid electric vehicles, characterized by a composite cathode material of lithium manganese oxide (LiMn2O4) and lithium nickel manganese cobalt oxide Li(NixCoyMn1-x-y)O2. Composite cathode material is an emerging technology that promises to combine the merits of several active materials into a hybrid electrode to optimize performance and reduce costs. In this study, the environmental assessment of one battery pack (with a nominal capacity of 11.4 kWh able to be used for about 140,000 km of driving) is carried out by using the Life Cycle Assessment methodology consistent with ISO 14040. The system boundaries are the battery production, the operation phase and recycling at the end of life, including the recovery of various material fractions. The composite cathode technology examined besides a good compromise between the higher and the lower performance of NMC and LMO cathodes, can present good environmental performances.The results of the analysis show that the manufacturing phase is relevant to all assessed impact categories (contribution higher than 60%). With regard to electricity losses due to battery efficiency and battery transport, the contribution to the use phase impact of battery efficiency is larger than that of battery transport. Recycling the battery pack contributes less than 11% to all of the assessed impact categories, with the exception of freshwater ecotoxicity (60% of the life cycle impact). The environmental credits related to the recovery of valuable materials (e.g. cobalt and nickel sulphates) and other metal fractions (e.g. aluminium and steel) are particularly relevant to impact categories such as marine eutrophication, human toxicity and abiotic resource depletion.The main innovations of this article are that (1) it presents the first bill of materials of a lithium-ion battery cell for plug-in hybrid electric vehicles with a composite cathode active material; (2) it describes one of the first applications of the life cycle assessment to a lithium-ion battery pack for plug-in hybrid electric vehicles with a composite cathode active material with the aim of identifying the “hot spots” of this technology and providing useful information to battery manufacturers on potentially improving its environmental sustainability; (3) it evaluates the impacts associated with the use phase based on primary data about the battery pack's lifetime, in terms of kilometres driven; and (4) it models the end-of-life phase of the battery components through processes specifically created for or adapted to the case study.

Cr3+ and F− co-doped lithium manganese oxide cathode for medium-temperature reserve primary cell

Medium-temperature molten salt reserve primary cell utilizes low-melting nitrate electrolyte, that is considered suitable for geothermal borehole as well as oil and gas exploration. In this work, Cr3+ and F− ions were introduced into spinel lithium manganate oxides by high-temperature solid-state method and verified by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The effects of fluorine content on the morphology and discharge performance of the LiCr0.1Mn1.9O4−xFx (0 ≤ x ≤ 0.5) have been studied in LiCr0.1Mn1.9O4−xFx/LiNO3-KNO3-Ca(NO3)2/Li-Mg-B system. Fluoride-doped samples have a significant improvement in discharge performance at the condition of 10 mA·cm−2 and 250 °C because of the stabilization of the crystal structure. Factors of operating temperature and current density have a significant effect on battery discharge performance, and the surroundings of 10 mA·cm−2 and 200–250 °C contributes the battery to achieve high performance. That indicates the LiCr0.1Mn1.9O4−xFx/LiNO3-KNO3-Ca(NO3)2/Li-Mg-B battery shows great potential in geothermal borehole as well as oil and gas exploration environment.

Controlling Expansion in Lithium Manganese Oxide Composite Electrodes via Surface Modification

Electrodes experience significant mechanical degradation at fast charging/discharging rates, ultimately leading to particle fracture and capacity loss. In this work, we investigate the role of an Au surface coating on the intercalation-induced strain changes in lithium manganese oxide (LiMn2O4, LMO) composite cathode electrodes. In-situ strain measurements are performed on free-standing composite electrodes to monitor lithium intercalation-induced deformations in the electrode. Interestingly, expansion in the Au-coated LMO electrodes are significantly smaller than LMO electrodes (without coating) at faster scan rates. Strain evolution is predicted based on elastic properties of the composite electrode and the intercalation-induced crystal structure changes in the LMO particles. Our results reveal that expansion can be controlled through coatings, suggesting promising material-based strategies to improve lifetime and performance of the batteries.