LiMn2O4 Research Articles

High-performance supercapacitor based on MnO/carbon nanofiber composite in extended potential windows

MnO/carbon nanofiber (CNF) composite is demonstrated as a high-performance electrode material for supercapacitors. LiMn2O4 (LMO) nanoparticle-decorated polyacrylonitrile (PAN) nanofibers are fabricated via electrospinning. Afterwards, LMO is converted to MnO and PAN is fully carbonized under synergistic annealing, resulting in MnO/CNF composite. The composite exhibits electrochemically active in an extended potential window of -1.0 – 0.8 V vs. Ag/AgCl. Moreover, a two-step electrochemical stimulation is observed for MnO at 0.0 V and 0.4 V corresponding to the phase transformations from MnO to Mn3O4 and from Mn3O4 to MnO2, respectively. As a result, the composite presents a high capacitance of 409.7 F g−1 at 1 A g−1 in -0.4 – 0.8 V vs. Ag/AgCl due to the phase transformations of MnO. Also, the composite owns 301.8 F g−1 at 1 A g−1 in -1.0 – 0.2 V vs. Ag/AgCl, which is 2.65 times the value of CNFs owing to the enhanced conductivity and surface redox by incorporating MnO. Finally, a supercapacitor with a working voltage of 1.8 V is realized using MnO/CNF composite as both negative and positive electrodes.

Synthesis, Modification, and Lithium‐Storage Properties of Spinel LiNi0.5Mn1.5O4

AbstractLithium‐ion batteries (LIBs) are currently widely applied in many aspects of life, but with the development, the capacity of lithium‐ion batteries can no longer meet the needs. One of the dominant factors to restricting the capacity of LIBs is the cathode materials. Among the derivatives of spinel cathode LiMn2O4 (LMO), LiNi0.5Mn1.5O4 (LNMO) has become one of the research promising cathode materials in the current LIBs due to its high working voltage (4.7 V) and large theoretical specific capacity (147 mAh g−1). However, the short cycle life of LNMO during the electrochemical process limits its large‐scale commercial applications. Thus, it is necessary to summarize and discuss the recent development of LNMO. Through comparison with LiMn2O4, the structure, electrochemical properties of LNMO, influence of Mn on the performance of LNMO, and the capacity fading mechanism are analyzed and discussed in detail. We also summarize the modification methods of LNMO and the influence of preparation methods on the structure and performance of LNMO. Finally, some prospects of LNMO cathode are put forward. This Review article can provide helpful references for future design and construction of LNMO.

Effects of oxidized Ketjen Black as conductive additives on electrochemical performance of the LiMn2O4@Al2O3 cathode in lithium-ion batteries

Metal oxide modified LiMn2O4 (LMO) is an effective method to improve the cycling performance. However, the metal oxide usually has low electronic conductivity, which lead to poor rate performance. Herein, Al2O3 modified LMO (LMO@AO) with enough oxygen vacancies have been prepared, and further constructed a highly conductive network of LMO@AO/KBO electrode though a self-assembly method using oxidized Ketjen Black (KBO) as conductive carbon additives. The KBO with a large number of oxygen-containing groups and show a negative charge state, while LiMn2O4@Al2O3 particles have a positive charge state. Therefore, the KBO can uniformly adsorption on the surface of LMO@AO particles, forming a continuously conductive network by self-assembly process. In this constructed architecture, a continuously conductive network can not only enhance the electronic conductivity but also facilitate the Li ions transport. As a result, the LMO@AO/KBO-3 electrode still shows excellent rate capability (a high reversible capacity of 83.3 mAh g−1 can be achieved at ultrahigh rate of 10 C) and superior long-term cycling stability (with a high capacity retention of 85.2% at 10 C even after 900 cycles).

Lithium metal anode with lithium borate layer for enhanced cycling stability of lithium metal batteries

Lithium metal is one of the most promising next generation anode materials to make a leap of the energy density of conventional lithium-ion batteries. However, lithium metal has fatal problems to overcome in cycling stability and safety. In this study, lithium metal is pre-treated to form a lithium borate layer (LBL) on the surface to suppress dendritic growth of lithium and stabilize the interface between the carbonate-based electrolyte and anode. The pre-treated lithium metal greatly enhances the cycling stability of the cells (Li || Li symmetric and LiMn2O4 (LMO) || Li cells). Especially, cycling test with the LMO || Li cell reveals the pre-treatment with boric acid is more effective approach than addition of boric acid in the electrolyte because water is continuously generated during charge/discharge in the latter case and it causes side reactions and degrades the cycling performance. The LBL along with LiF stabilizes the solid electrolyte interface (SEI) layer and suppresses the dendritic growth of lithium. Due to the lithium-ion conducting ability of lithium borate, the pre-treated lithium anode also shows lower interfacial resistance than the pristine lithium and enhances rate capability.

Green and low-cost acetate-based electrolytes for the highly reversible zinc anode

A highly concentrated solution of potassium, lithium and zinc acetate is proposed as green “Water-in-Salt” electrolyte (WiSE). In this halide-free electrolyte, investigated by classical Molecular Dynamics simulations, differential scanning calorimetry (DSC) and Raman spectroscopy, the water molecules are coordinated by the acetate anion as well as the various cations. As a result of the strong coordination of water molecules, the WiSE enables outstanding zinc (Zn) plating/stripping average Coulombic efficiency (CE) (99.6%) and long-term cycling stability. Dual ion cells using this electrolyte and featuring the Zn metal anode and either LiFePO4 (LFP) or spinel LiMn2O4 (LMO)-based cathodes deliver discharge capacity of 155 mA h g−1 and 121 mA h g−1 at 0.05C, respectively. The Zn/LFP cells demonstrate better cycling stability compared to Zn/LMO, which is attributed to the more stable crystal structure of LFP.

Structure and activity of lysozyme on binding to lithium-manganese oxide nanocomposites prepared from seabed nodule

In this work, synthesis of lithium-manganese dioxide from natural manganese (Mn) bearing resources is described. The purified nodule leach solution is taken as the potential source for the fabrication of Li–MnO2 nanocomposite (NC). Herein, we reported a simple room temperature chemical precipitation route for the synthesis of lithium-manganese dioxide NC in absence of surface directing reagent/template. Also, we investigated the molecular interactions of the prepared NCs with lysozyme (Lyz) to understand the biocompatibility of these NCs. A systematic study of the interactions between NC and biomolecule plays a key role in understanding the fate of NCs in biological applications like biosensing, imaging, and drug delivery etc. The conformational changes of Lyz in NC solutions are characterized by using circular dichroism and FTIR which revealed that the secondary structure of Lyz remains stable in presence of NCs. Moreover, we studied the activity of Lyz using Micrococcus lysodeikticus cells. The results indicate that the NC prepared at 1 M LiOH concentration showed better lysis activity as compared to NC prepared at low LiOH concentration. This work provides a simple preparation route for the synthesis of NCs from natural Mn resources and recommends the use of different NCs for further biological studies.

Short Review: Timeline of the Electrochemical Lithium Recovery System Using the Spinel LiMn2O4 as a Positive Electrode

Various lithium recovery technologies have been developed as securing lithium resources has become increasingly important. Among these technologies, the electrochemical lithium recovery (ELR) system is a rapid and eco-friendly extraction method that has been studied recently. In this paper, an ELR system using a spinel-type LiMn2O4 (LMO) is briefly reviewed. As LMO electrodes have high Li+ selectivity and stability compared to other lithium battery cathodes, they have been widely used as positive electrodes for the ELR system. This paper summarizes the system proposal, LMO electrode modification, system analysis, and industrial applications. Perspectives of the ELR technology are presented considering the progress of the research.

Enabling Aqueous Processing for Low/No-Cobalt Lithium-Ion Battery Cathode Active Materials

Industrially, lithium-ion battery cathodes are manufactured through a wet slurry mixing and coating process. There is great interest in replacing the presently-used N-methyl-2-pyrrolidone (NMP) solvent with water due to the cost and toxicity associated with NMP. In this study, the modifications made to the active materials as a result of water exposure were studied and two materials, LiMn2O4 (LMO) and LiNi0.8Co0.15Al0.05O2 (NCA), were assembled in high-performing aqueous-processed cathodes for the first time.Five cathode active materials were the subject of this study: LiCoO2 (LCO), LiFePO4 (LFP), LMO, NCA, and LiNi0.5Mn0.3Co0.2O2 (NMC532). All materials exposed to DI water exhibited rapid increases in pH over the first 10 min, with stable pH values ranging from 9.0 (LFP and LMO) to 12.5 (NCA). Given that the protective aluminum oxide layer on the current collector breaks down at a pH of 8.5, corrosion is predicted for all materials, with NCA being the most extreme case. Pristine samples of the same five materials were submerged in water for 24 h, then the moisture was dried in a vacuum oven. The crystal structures of these materials (henceforth referred to as the wetted samples) were evaluated using X-ray diffraction and compared with pristine samples. No changes were observed in the crystal structure of any material as confirmed by Rietveld refinement. X-ray photoelectron spectroscopy was used to evaluate the changes of the surface composition of each wetted and pristine material.Based on inductively coupled plasma-mass spectrometry results, the amount of Li and transition metal leaching in water was found to be independent of time in excess of 1 h, and the amount of Li leaching in water for NCA was found to be five times that of NMC532 and more than 30 times that of the other materials. As a result, using a traditional aqueous slurry formulation (active material, carbon black, emulsion binder, carboxymethylcellulose thickener) resulted in a severely cracked and unusable NCA cathode. By including high-molecular weight polyacrylic acid (PAA), the adhesion of the cathode was restored. Half coin cells of this PAA-processed and an NMP-processed NCA cathode were constructed using punches with 1.7 mAh·cm-2 areal capacity and a charge and discharge rate of C/3 between 3.0-4.3 V. The initial capacity of the PAA-processed NCA cathode was slightly lower (176.3 mAh·g-1 to 185.2 mAh·g-1), though it did exhibit better capacity retention through 100 cycles (84.2% to 78.1%).

Role of Ni, Mn and Co in Layered Rock Salt Cathode Materials for Li-Ion Battery: A DFT Study

Li-ion battery (LIB) has high energy/power density and long cycle life among other battery systems. LiCoO2(LOC) is a commonly used LIB cathode material which has a layered rock salt structure. To meet environmental needs, especially for the reduction of CO2, electrification of the automotive applications requires high volume of batteries. Here, Co which is a key element of LIB has potential supply risks due to its geological availability and value chains. Although, low-Co and high Ni cathode materials such as LiNiMnCoO2 (NMC) or LiNiCoAlO2 (NCA) have been developed by Edisonian approach, the role of Co in the cathode materials with layered rock salt structure is still not clear. To understand the role of Co, we conducted a comprehensive study with modeling and simulation backed up by the synchrotron X-ray experiment. A series of density functional theory (DFT) calculation was performed using the Vienna Ab initiation Simulation Package (VASP)[1,2] within the projector augmented-wave method and generalized-gradient approximation (GGA). All calculations were performed employing PBE-GGA+U. Change in the charge density distributions and thestructure parameters at different states of charge (SOCs) were calculated for mono-transition-metal oxidessuch as LCO, LiNiO2 (LNO) and LiMnO2 (LMO) as well as ternary-transition material NMC with different composition ratio, ie NMC111, NMC622, NMC811. Figure 1 shows Bader charge analysis[3] result for each elements in LCO, LNO and LMO as a function of the SOC. Detailed analysis with experimental results of XAFS and XRD, and will be discussed in the meeting.[1] P. E. Blöch, Phys. Rev. B 50, 17953 (1994).[2] G. Kresse et al., Phys. Rev. B 59, 1758 (1999).[3] G. Henkelman, A. Arnaldsson, and H. Jónsson, Comput. Mater. Sci. 36, 354-360 (2006) Figure 1

Mechano-Electrochemical Simulation of Pouch Cells with Electrodes Containing Multiple Active Materials

Automotive battery manufacturers are working to improve individual cell and overall pack design by increasing their performance, durability, and range, while reducing cost and active material volume change is one of the more complex aspects that needs to be considered during this process. To improve the balance between cost, stability, performance, and volume change behavior, some cell designers have introduced the use of multiple active materials within the same composite electrode. For example, LiMn2O4 (LMO) and LiNi1/3Co1/3Mn1/3O2 (NMC) active materials are both included in cathodes to benefit from this balance. In anodes, some designers have included both silicon and graphite to maximize gravimetric capacity while maintaining a tolerable degree of volume expansion to prevent damage to the cell and pack structure.While the inclusion of multiple active materials can be used to better tune electrode performance, stability, and volume change for specific applications, the modeling of these electrodes is significantly more complicated. Previously, Albertus et. al developed a model to account for multiple active materials within the same positive electrode.(1) Their model took the concept of a pseudo-two dimensional Li-ion cell model and incorporated multiple pseudo second-dimensions, which correlates to the radial direction of a theoretical active material particle. Therefore, they could account for each active material separately, where previously, an average particle radius, average film resistance, and average equilibrium potential would be assumed for the total electrode.In the study shown here, we build upon this modeling concept by incorporating our previously developed mechano-electrochemical equations to account for active material volume change.(2-5) Figure 1 shows an example of equilibrium potentials for two anode active materials as a function of lithiation fraction. The difference between these equilibrium potentials will dictate the preferential lithiation of the materials, and thus, the rate at which each material undergoes lithiation-based volume change. This allows for the simulation of volume change in diffusion-governed (high rate) or kinetic-governed (low rate) charge and discharge.The relationships between anode/cathode capacity, electrode voltages, and active material volume will be discussed. References P. Albertus, J. Christensen and J. Newman, Journal of The Electrochemical Society, 156, A606 (2009).T. R. Garrick, K. Higa, S.-L. Wu, Y. Dai, X. Huang, V. Srinivasan and J. W. Weidner, Journal of The Electrochemical Society, 164, E3592 (2017).T. R. Garrick, X. Huang, V. Srinivasan and J. W. Weidner, Journal of The Electrochemical Society, 164, E3552 (2017).T. R. Garrick, K. Kanneganti, X. Huang and J. W. Weidner, Journal of The Electrochemical Society, 161, E3297 (2014).D. J. Pereira, J. W. Weidner and T. R. Garrick, Journal of The Electrochemical Society, 166, A1251 (2019).D. J. Pereira, M. A. Fernandez, K. C. Streng, X. X. Hou, X. Gao, J. W. Weidner, and T. R. Garrick, Journal of The Electrochemical Society, 167, 080515 (2020). Figure 1. Equilibrium potential as a function of lithiation fraction for two anode active materials. Figure 1

Suitability of Ethyl Cellulose As a Binder in Positive Electrode of Aqueous Li-Ion Battery

Novel materials for energy storage devices need to be affordable, durable, safe and environmentally friendly. PVDF, which is the most popular polymer used as a binder in battery cathode electrodes, requires the use of and toxic solvents for processing, such as N-methyl-pyrrolidone (NMP).1 Ethyl cellulose is a biodegradable and water-insoluble polymer. Ethyl cellulose based slurry can be prepared using ethanol as solvent, which makes the process cheaper and more sustainable. Replacing PVDF with more environmentally friendly binder like ethyl cellulose in positive electrode of aqueous Li-ion battery would be beneficial in many ways. It would shorten the assembly procedure due to high speed of solvent evaporation, there are no strict requirements for humidity control and the recycling procedure is easier as there are no fluorinated compounds.2 Therefore, this replacement would enable to produce safer and cheaper energy storage devices.In this work electrodes with different composition have been described using galvanostatic charging-discharging and cyclic voltammetry. LiMn2O4 (LMO) has been used as active material for cathode, carbon black Super P as conductive additive and PDVF or ethyl cellulose as a binder. The electrodes were prepared using different mass ratios of conductive additive and binder to evaluate the performance of this sustainable polymer. Using ethyl cellulose as a binder, discharge capacity 100 mAhg− 1 was achieved at 0.2C rate for LMO cathode which is comparable to the results obtained with PVDF as a binder. 500 cycles at the rate of 1C showed somewhat better capacity retention for electrodes prepared using PVDF. However, the results show that ethyl cellulose is a promising option to replace PVDF as cathode binder in aqueous systems. Further optimization is needed to prepare these novel and sustainable cathodes for aqueous Li-ion battery.The research was supported by the Estonian Research Council grant PUTJD956 and Magnus Ehrnrooth Foundation.

Morphology-controlled synthesis of RGO/LiMn2O4 nanocomposite as cathodic Li-ion battery materials and its lithium insertion/extraction study

In the present work, β- MnO2 with the morphology of stacked nanowire-decorated nanorods and γ- MnO2 with morphology of nanosheets have been prepared by a simple and new one-step hydrothermal method without the application of any surfactants or templates. Then, the MnO2 nanostructures converted to the LiMn2O4 (LMO) with solid-state reaction. RGO and LMO/RGO nanocomposites were successfully synthesized and characterized using FT-IR, XRD, EDS, and SEM methods. The lithiation/delithiation electrochemical behaviors of nanocomposites were investigated employing electrochemical galvanostatic charge–discharge and electrochemical impedance spectroscopy. The nanorod-decorated LMO composite delivered the highest discharge capacitance of 141 mAh g−1 at 700 mA g−1 current density, with the capacity retention as high as 92% observed after 50 cycles.

LiNi0.5Mn1.5O4-based hybrid capacitive deionization for highly selective adsorption of lithium from brine

In recent years, the demands for lithium are increasing sharply with the fast development of electrical vehicles, new green energy and portable electronic devices. To meet the demands, selective recovery of lithium from brine/seawater has attracted extensive attention. LiMn2O4 (LMO) is a good redox material for lithium recovery. However, the dissolution of Mn is inevitable during the redox process which can lead to severe capacity decay and poor cycle performance. In this paper, LiNi0.5Mn1.5O4 (LNMO) nanoparticles were prepared through one-step solid-state sintering and applied as a positive electrode in the hybrid capacitive deionization cell for lithium recovery. Cyclic voltammetry (CV) scan of the LNMO electrode in LiCl aqueous solution presented clear redox peaks, illustrating the reversible intercalation/de-intercalation of Li+ into/from LNMO; while the Na+, K+, Mg2+ and Ca2+ cations had negligible intercalation. Combined with an activated carbon (AC) negative electrode, the hybrid capacitive deionization cell (LNMO||AC) was assembled to selectively adsorb lithium, arriving at the adsorption amount of ~260 µmol/g, almost three times higher than that of the symmetric AC cell (AC||AC). Even in the Mg2+ and Li+ mixed binary salt solution at a high CMg2+/CLi+ ratio of 30, LNMO remained high selectivity to Li+ with the separation factor of ~104 achieved. In the synthetic brine water containing various salts, the LNMO||AC cell kept excellent selectivity to Li+ with the adsorption amount still remaining ~230 µmol/g. And the cell can preserve a retention of ~86% after 100 cycles, much higher than the LMO||AC cell (~50%). Meanwhile, neither Mn2+ nor Ni2+ were found in the cycling solution of LNMO||AC cell. Nevertheless, the LMO||AC cell deteriorated gradually with the dissolution loss ratio of Mn in LMO close to 40%. Such excellent selectivity and high stability of LNMO enable it applicable for practical lithium recovery application, superior to LMO.

Enhanced Electrochemistry of Carbon Supported Functionalized Nanocomposite Cathode for Aqueous Lithium‐ion Batteries

AbstractA novel carbon supported LiMn2O4 nanocomposite framework has been explored to resolve multiple barriers associated with lithium manganese oxide cathodes for aqueous LIB systems. Here, we have successfully synthesized an architecturally stable AlF3−LiMn2O4/rGO composite with improved electron transfer kinetics and CV peak currents proportional to the square root of scan rate. The synergy between graphene and aluminium trifluoride enhances the intrinsic electrochemical properties of pristine LiMn2O4 (LMO) and reduced Mn+3 dissolution. The unique composite effectively reduced Li+ diffusion distances with less polarization as it effectively accommodates the structural transformation during Li+ ion charge and discharge. The electrochemical interrogation revealed faster charge transportation and decrease in charge transfer resistance due to inhibition of the pronounced pile‐up of Li+ ions and undesired Mn3+ ions on the surfaces. The electrochemical performances were tested in LiNO3 aqueous electrolyte and the cell delivered a capacity of 90 mA h g−1 based on the total weight of the active electrode materials. This aqueous LIB cathode system provides a promising alternative for safe, cost‐effective and scalable energy storage with tolerance against misuse.

Flexible aqueous lithium-ion batteries with ultrahigh areal capacity and long cycle life

Practical application of flexible batteries have been hindered by low areal capacity, low stability, and safety concerns. This work reports a facile and scalable infiltration method to fabricate free-standing three-dimensional (3D) flexible electrodes using LiTi2(PO4)3 (LTP) and LiMn2O4 (LMO) as examples for aqueous Li-ion batteries. Benefiting from the unique 3D electrode architecture with fast electron and ion transport, flexible LTP-LMO pouch cells deliver an ultrahigh areal capacity (e.g., 3–23 mAh cm−2, LTP loading = 24–200 mg cm−2), high rate capability, and stable cycling stability (e.g., 93% and 72% capacity retention after 500 and 3000 cycles, respectively, at 14–15 mA cm−2). High mechanical and electrochemical stability of the cell is demonstrated with a high capacity retention of 96% after 1000 dynamic bending cycles. Pouch cells with a high capacity (0.53 Ah for 4 × 6 cm2 cell) and high voltage (3 V/9 V) are demonstrated. This work offers a low-cost and effective strategy to fabricate high areal capacity electrodes with stable electrochemical performance, high mechanical strength, and excellent flexibility.

Accurate Control of Initial Coulombic Efficiency for Lithium-rich Manganese-based Layered Oxides by Surface Multicomponent Integration.

Low initial Coulombic efficiency (ICE) is an obstacle for practical application of Li-rich Mn-based layered oxides (LLOs), which is closely related with the irreversible oxygen evolution owing to the overoxidized reaction of surface labile oxygen. Here we report a NH4 F-assisted surface multicomponent integration technology to accurately control the ICE, by which oxygen vacancies, spinel-layered coherent structure, and F-doping are skillfully integrated on the surface of treated LLOs microspheres. Though the regulation on the removed amount of labile oxygen by surface integrated structure, the ICE of LLOs cathodes can adjust from starting value to 100 %. X-ray absorption spectroscopy, refined X-ray diffraction, and scanning transmission electron microscopy show that the removed labile oxygen mainly comes from Li2 MnO3 -like structure. Even operating at a high cut-off voltage of 5 V, the capacity retention of integrated sample at 200 mA g-1 is still larger than 98 % after 100 cycles.

Aqueous Rechargeable Li+ /Na+ Hybrid Ion Battery with High Energy Density and Long Cycle Life.

The practical application of aqueous rechargeable batteries is hampered by the low energy density and poor cycle stability, which mostly arises from the corrosion of cathode current collector, exfoliation of active material, and narrow electrochemical stability window of aqueous electrolyte. A light-weight and low-cost cathode current collector composed of graphite and carbon nanotube coated on nylon membrane exhibiting corrosion resistance and strong adhesion is developed. Also, a modified aqueous electrolyte with the addition of urea whose window is expanded to ≈3.2 V is developed that contributes to the formation of solid-electrolyte interphase on surfaces of electrodes. LiMn2 O4 /NaTi2 (PO4 )3 Li+ /Na+ hybrid ion battery using such aqueous electrolyte and current collector is demonstrated to cycle up to 10 000 times with low cost (60 dollars per kWh) and high energy density (100 Wh kg-1 ) for stationary energy storage and electronic vehicles applications.

An "Ether-In-Water" Electrolyte Boosts Stable Interfacial Chemistry for Aqueous Lithium-Ion Batteries.

Aqueous batteries are promising devices for electrochemical energy storage because of their high ionic conductivity, safety, low cost, and environmental friendliness. However, their voltage output and energy density are limited by the failure to form a solid-electrolyte interphase (SEI) that can expand the inherently narrow electrochemical window of water (1.23 V) imposed by hydrogen and oxygen evolution. Here, a novel (Li4 (TEGDME)(H2 O)7 ) is proposed as a solvation electrolyte with stable interfacial chemistry. By introducing tetraethylene glycol dimethyl ether (TEGDME) into a concentrated aqueous electrolyte, a new carbonaceous component for both cathode-electrolyte interface and SEI formation is generated. In situ characterizations and ab initio molecular dynamics (AIMD) calculations reveal a bilayer hybrid interface composed of inorganic LiF and organic carbonaceous species reduced from Li+ 2 (TFSI- ) and Li+ 4 (TEGDME). Consequently, the interfacial films kinetically broaden the electrochemical stability window to 4.2 V, thus realizing a 2.5 V LiMn2 O4 -Li4 Ti5 O12 full battery with an excellent energy density of 120 W h kg-1 for 500 cycles. The results provide an in-depth, mechanistic understanding of a potential design of more effective interphases for next-generation aqueous lithium-ion batteries.

The improved performance of spinel LiMn2O4 cathode with micro-nanostructured sphere-interconnected-tube morphology and surface orientation at extreme conditions for lithium-ion batteries

Recently, spinel-type LiMn2O4 (LMO) cathode has attracted great attention to mitigate manganese dissolution especially at elevated temperature. In this work, LMO with surface specific facets and different morphologies are successfully controlled synthesized via a facile solvothermal-lithiation method. It suggests that microspheres, micro-tubes and hybrid sphere-interconnected-tube microstructures with different surface lattice orientation using urea, oxalic acid and mixture of urea and oxalic acid as precipitants at solvothermal stage, respectively. Specifically, LMO microspheres (LMO-MS) display (111) facets and the micro-tubular LMO materials (LMO-MT) exhibit the high index lattice (311). It is more interesting is that hybrid sphere-interconnected-tube microstructures (LMO-MST) are clearly observed the densest (111) facets at the micro-spherical surface and a new (111) plane appearance on the surface of microtubes. LMO-MST demonstrates excellent cycling performance (84.3 % capacity retention after 1000 cycles at 10 C) and superior rate capability up to 10 C (124.2 mAh g−1 at 10 C). The electrochemical performances of LMO-MST cathodes are also investigated at elevated (55°C) and lower (-5°C) temperatures, under which LMO-MST still maintains optimal cycling stability. The superior electrochemical performance of LMO-MST cathodes can be attributed to the unique sphere-bridged-tube seamless outer structure and the preferentially exposed stable facets on the crystal surface.

Decimal Solvent-Based High-Entropy Electrolyte Enabling the Extended Survival Temperature of Lithium-Ion Batteries to −130 °C

Freezing and crystallization of commercial ethylene carbonate-based binary electrolytes, leading to irreversible damage to lithium-ion batteries (LIBs), remain a significant challenge for the survi...