O2 Cathode Research Articles

Stabilizing High-Voltage Performance of Nickel-Rich Cathodes via Facile Solvothermally Synthesized Niobium-Doped Strontium Titanate.

Ni-rich layered ternary cathodes are promising candidates thanks to their low toxic Co-content and high energy density (∼800 Wh/kg). However, a critical challenge in developing Ni-rich cathodes is to improve cyclic stability, especially under high voltage (>4.3 V), which directly affects the performance and lifespan of the battery. In this study, niobium-doped strontium titanate (Nb-STO) is successfully synthesized via a facile solvothermal method and used as a surface modification layer onto the LiNi0.8Co0.1Mn0.1O2 (NCM811) cathode. The results exhibited that the Nb-STO modification significantly improved the cycling stability of the cathode material even under high-voltage (4.5 V) operational conditions. In particular, the best sample in our work could provide a high discharge capacity of ∼190 mAh/g after 100 cycles under 1 C with capacity retention over 84% in the voltage range of 3.0-4.5 V, superior to the pristine NCM811 (∼61%) and pure STO modified STO-811-600 (∼76%) samples under the same conditions. The improved electrochemical performance and stability of NCM811 under high voltage should be attributed to not only preventing the dissolution of the transition metals, further reducing the electrolyte's degradation by the end of charge, but also alleviating the internal resistance growth from uncontrollable cathode-electrolyte interface (CEI) evolution. These findings suggest that the as-synthesized STO with an optimized Nb-doping ratio could be a promising candidate for stabilizing Ni-rich cathode materials to facilitate the widespread commercialization of Ni-rich cathodes in modern LIBs.

Facilitating an Ultrastable O3-Type Cathode for 4.5 V Sodium-Ion Batteries via a Dual-Reductive Coupling Mechanism.

O3-type layered oxides for sodium-ion batteries (SIBs) have attracted extensive attention due to their inherently sufficient Na content, which have been considered as one of the most promising candidates for practical applications. However, influenced by the irreversible oxygen loss and the phase transition of O3-P3, the O3-type cathodes are always limited by low cutoff voltages (typically <4.2 V), restraining the full release of the capacity. In this study, we originally propose a dual-reductive coupling mechanism in a novel O3-type Na0.8Li0.2Fe0.2Ru0.6O2 cathode with the suppressed O3-P3 phase transition, aiming at improving the reversibility of oxygen redox at high voltage regions. Consequently, thanks to the formation of the strong covalent Fe/Ru-(O-O) bonding and inhibited slab gliding from the O to P phase, the cathode delivers the preeminent cyclic stability among the numerous O3-type cathodes within a high voltage of 4.5 V (a capacity retention of 95.4% after 100 cycles within 1.5-4.5 V). More importantly, HAADF-STEM and 7Li solid-state NMR results reveal the absence of transition metal migration and the presence of reversible Li migration during cycling, which further contributes to the improved structural robustness of the cathode. This study proposes an innovative strategy to boost the reversibility of anionic redox and to achieve stable high-voltage O3-type layered oxides, promoting the further development of SIBs.

Constructing sulfur-rich interphase to promote the cycle stability of graphite/LiNi0.8Co0.1Mn0.1O2 pouch battery at elevated temperature

Lithium-ion batteries (LIBs) with LiNi0.8Co0.1Mn0.1O2 (NCM811) cathodes have a high energy density, but their long-cycle performance, especially at high temperature, should still be improved due to the instability of the NCM811 cathode-electrolyte interphase. In this work, 2, 2, 2-Trifluoroethyl p-Toluenesulfonate (TPTS) is introduced as a functional film-forming electrolyte additive design to improve the long-term stability of graphite/NCM811 batteries. The preferential redox reactions of TPTS molecules play a pivotal role in fostering the creation of a sulfur-riched interphase, characterized by low impedance. This interphase works to fortify the interfacial structure, effectively inhibiting the dissolution of transition metal ions. Therefore, in comparison to the graphite/NCM811 pouch batteries lacking additive, TPTS enhance the long-cycle capacity retention from 47 % to 80 % after 450 cycles at 45 °C. What's more, TPTS suppresses outgassing and demonstrates enhanced capacity maintenance for the battery even after storage at 60 °C. This work not only demonstrates the stabilizing impacts of TPTS on the electrode-electrolyte interphase and its enhancement of cycling performance at elevated temperatures but also introduces a novel approach for the practical utilization of functional electrolytes matching high-nickel LIBs.

High stability of Cu-doped O3-type NaNi1/3Fe1/3Mn1/3O2 cathode material for sodium-ion battery

High stability of Cu-doped O3-type NaNi1/3Fe1/3Mn1/3O2 cathode material for sodium-ion battery

Single-Crystal P2-Na0.67Mn0.67Ni0.33O2 Cathode Material with Improved Cycling Stability for Sodium-Ion Batteries.

Layered oxides constitute one of the most promising cathode materials classes for large-scale sodium-ion batteries because of their high specific capacity, scalable synthesis, and low cost. However, their practical use is limited by their low energy density, physicochemical instability, and poor cycling stability. Aiming to mitigate these shortcomings, in this work, we synthesized polycrystalline (PC) and single-crystal (SC) P2-type Na0.67-δMn0.67Ni0.33O2 (NMNO) cathode materials through a solid-state route and evaluated their physicochemical and electrochemical performance. The SC-NMNO cathode with a large mean primary particle size (D50) of 12.7 μm was found to exhibit high cycling stability leading to 47% higher capacity retention than PC-NMNO after 175 cycles at 1C rate in the potential window 4.2-1.5 V. This could be attributed to the effective mitigation of parasitic side reactions at the electrode-electrolyte interface and suppressed intergranular cracking induced by anisotropic volume changes. This is confirmed by the lower volume variation of SC-NMNO (ΔV ∼ 1.0%) compared to PC-NMNO (ΔV ∼ 1.4%) upon charging to 4.2 V. Additionally, the SC-NMNO cathode displayed slightly higher thermal stability compared to PC-NMNO. Both cathodes exhibited good chemical stability against air and water exposure, thus enabling material storage/handling in the ambient atmosphere as well as making them suitable for aqueous processing. In this regard, PC-NMNO was investigated with two low-cost aqueous binders, carboxymethyl cellulose, and sodium trimetaphosphate, which exhibited higher binding strength and displayed excellent electrochemical performance compared to PVDF, which could potentially lead to significant cost reduction in electrode manufacturing.

Revealing the origin of enhanced structural stability for nickel-rich LiNi0.83Co0.11Mn0.06O2 cathodes in situ modified with multifunctional polysiloxane

Multifunctional polysiloxane (MPS) layer is elaborately constructed on the surface of LiNi0.83Co0.11Mn0.06O2 (NCM83) particles via in situ hydrolysis-polycondensation of tetraethyl orthosilicate. Impressively, optimal NCM83 (NCM83-2) electrode covered with average 7 nm-thickness of fresh MPS layer delivers improved capacity retention ratio of 81.8 % after 150 cycles at 25 °C and retains the value of 78.7 % after 200 cycles at 60 °C and 1.0 C. Moreover, NCM83-2 electrode presents lower polarization degree with sluggish growth of the capacity platform. The significant advantages of NCM83-2 can be interpreted by the fact that the MPS layer effectively mitigates microcracks generation by inhibiting phase transition and lattice oxygen loss. Moreover, the MPS protective layer suppresses the thickening of cathode electrolyte interphase film and boosts the structural stability of NCM83 electrode to optimize electrochemical properties. Therefore, this strategy may provide promising enlightenments for preserving structural integrity and improving interfacial stability of nickel-rich cathodes for lithium-ion batteries.

Improving storage performance and lattice oxygen stability of single crystal LiNi0.925Co0.03Mn0.045O2 by integrating utilization of surface residual lithium and lattice modulation

In lithium-ion batteries, Ni-rich single crystal cathode material (Ni > 90 %) is a promising cathode material, but it has not yet been put into commercial application due to defects such as structural degradation, air sensitivity and thermal instability. In this paper, the residual lithium compounds on the surface of high-nickel materials are not useless. Li3PO4 coated and Mg2+ doped single crystal cathode materials (SC-NCM-MP) were successfully prepared by precisely controlling the amount of MgHPO4 by titration and reacting with lithium compounds left on the surface of LiNi0.925Co0.03Mn0.045O2 (SC-NCM) cathode materials. The SC-NCM-MP samples exhibit better lattice oxygen stability, Li-ion mobility, storage performance and electrochemical performance, with a retention of 89.36 % after 100 cycles, which is much higher than 79.78 % of SC-NCM.

Understanding the Effects of Bi Modification on the Properties of Ni‐rich Cathodes

AbstractWith the skyrocketing market demands for energy storage, lithium ions batteries (LIB) with higher energy density are urgently needed. Cathodes play a critical role in determining the energy density of LIB, and the most popular one is Ni‐rich cathode due to its high capacity. However, due to the fast structural degradation, Ni‐rich cathode materials should be further modified to achieve higher stability. Herein, we introduce bismuth ions in LiNi0.83Co0.11Mn0.06O2 cathodes by adding Bi2O3 during sintering to optimize the specific capacity and cycle stability. By adding 0.1 % mol Bi, the Li+ diffusion and structural stability are effectively optimized, leading to improved electrochemical performances. The modified sample delivers much higher specific capacity (222.9 mAhg−1, 0.05 C) than unmodified sample (204 mAhg−1, 0.05 C). Meanwhile, the specific capacity of optimized sample after 100 cycles at 0.33 C is 27.75 mAhg−1 higher than that of unmodified sample. Therefore, this work demonstrates that Bi modification can be regarded as a possible solution to optimizing the electrochemical performance of Ni‐rich cathodes.

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

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

Composition and state prediction of lithium-ion cathode via convolutional neural network trained on scanning electron microscopy images

High-throughput materials research is strongly required to accelerate the development of safe and high energy-density lithium-ion battery (LIB) applicable to electric vehicle and energy storage system. The artificial intelligence, including machine learning with neural networks such as Boltzmann neural networks and convolutional neural networks (CNN), is a powerful tool to explore next-generation electrode materials and functional additives. In this paper, we develop a prediction model that classifies the major composition (e.g., 333, 523, 622, and 811) and different states (e.g., pristine, pre-cycled, and 100 times cycled) of various Li(Ni, Co, Mn)O2 (NCM) cathodes via CNN trained on scanning electron microscopy (SEM) images. Based on those results, our trained CNN model shows a high accuracy of 99.6% where the number of test set is 3840. In addition, the model can be applied to the case of untrained SEM data of NCM cathodes with functional electrolyte additives.

Synthesis and Characterization of Na2/3[Fe1/2Mn1/2]O2 Cathode Material for Sodium Ion Batteries

&lt;p&gt;&lt;strong&gt;Abstract. &lt;/strong&gt;Recently,&lt;strong&gt; &lt;/strong&gt;Na&lt;sub&gt;2/3&lt;/sub&gt;[Fe&lt;sub&gt;1/2&lt;/sub&gt;Mn&lt;sub&gt;1/2&lt;/sub&gt;]O&lt;sub&gt;2&lt;/sub&gt; has received attention as a potential candidate material for cathode sodium-ion batteries. However, this material was synthesized by a solid-state process, resulting in larger particle size and nonuniform morphology. The larger particle size will sluggish the Na ion diffusion. Here we report the synthesis of Na&lt;sub&gt;2/3&lt;/sub&gt;[Fe&lt;sub&gt;1/2&lt;/sub&gt;Mn&lt;sub&gt;1/2&lt;/sub&gt;]O&lt;sub&gt;2&lt;/sub&gt; using a simple sol-gel process. The X-ray diffraction revealed that the sample was identified as Na&lt;sub&gt;2/3&lt;/sub&gt;[Fe&lt;sub&gt;1/2&lt;/sub&gt;Mn&lt;sub&gt;1/2&lt;/sub&gt;]O&lt;sub&gt;2&lt;/sub&gt; with a hexagonal crystal structure. However, the impurities are formed at diffraction angles of 36.28°, 45.03°, and 51.23°. Calcination temperature affects the formation of the crystal phase, grain growth, morphology, and particle size. Our findings provide valuable insight into the development of Na&lt;sub&gt;2/3&lt;/sub&gt;[Fe&lt;sub&gt;1/2&lt;/sub&gt;Mn&lt;sub&gt;1/2&lt;/sub&gt;]O&lt;sub&gt;2&lt;/sub&gt; material with desirable properties.&lt;/p&gt;&lt;p&gt; &lt;/p&gt;&lt;p&gt;&lt;strong&gt;Keywords:&lt;/strong&gt;&lt;/p&gt;&lt;p&gt;Sol-Gel, Solid State, Grain Growth, Calcination, Na&lt;sub&gt;2/3&lt;/sub&gt;[Fe&lt;sub&gt;1/2&lt;/sub&gt;Mn&lt;sub&gt;1/2&lt;/sub&gt;]O&lt;sub&gt;2&lt;/sub&gt;&lt;/p&gt;&lt;p&gt; &lt;/p&gt;

Measuring Heat Dissipation and Entropic Potential in Battery Cathodes Made with Conjugated and Conventional Polymer Binders Using Operando Calorimetry.

This study explores the influence of electronic and ionic conductivities on the behavior of conjugated polymer binders through the measurement of entropic potential and heat generation in an operating lithium-ion battery. Specifically, the traditional poly(vinylidene fluoride) (PVDF) binder in LiNi0.8Co0.15Al0.05O2 (NCA) cathode electrodes was replaced with semiconducting polymer binders based on poly(3,4-propylenedioxythiophene). Two conjugated polymers were explored: one is a homopolymer with all aliphatic side chains, and the other is a copolymer with both aliphatic and ethylene oxide side chains. We have shown previously that both polymers have high electronic conductivity in the potential range of NCA redox, but the copolymer has a higher ionic conductivity and a slightly lower electronic conductivity. Entropic potential measurements during battery cycling revealed consistent trends during delithiation for all of the binders, indicating that the binders did not modify the expected NCA solid solution deintercalation process. The entropic signature of polymer doping to form the conductive state could be clearly observed at potentials below NCA oxidation, however. Operando isothermal calorimetric measurements showed that the conductive binders resulted in less Joule heating compared to PVDF and that the net electrical energy was entirely dissipated as heat. In a comparison of the two conjugated polymer binders, the heat dissipation was lower for the homopolymer binder at lower C-rates, suggesting that electronic conductivity rather than ionic conductivity was the most important for reducing Joule heating at lower rates, but that ionic conductivity became more important at higher rates.

Enhancing Structural Rigidity of Ultrahigh-Ni Oxide Through Al and Nb Dual-Bulk-Doping for High-Voltage Lithium-Ion Batteries.

The pursuit of high energy densities propels the design of next-generation nickel-based layered oxide cathodes. The utilization of low-cobalt, ultrahigh-nickel layered oxide cathodes, and the extension of operating voltages promise enhanced energy density. However, stability and safety face challenges associated with nickel content, including structural degradation, lattice oxygen evolution, and thermal instability. In this study, a promising strategy of Al and Nb dual-bulk-doping is presented in high-Ni cathode materials of LiNi0.96Co0.04O2 (NC) to stabilize the bulk structure, suppress oxygen release, and attain superior electrochemical performance at high voltages. The introduction of Al and Nb effectively raises the migration energy of Ni2+ into Li sites and stabilizes lattice oxygen through strengthened Al─O and Nb─O bonds. Furthermore, the substitution of high-valence Nb ions reduces the charge depletion of lattice oxygen and induces an ordered microstructure. The Al and Nb dual-bulk-doping strategy mitigates strain and stress associated with the H2↔H3 phase transition, reducing the generation and propagation of microcracks. The resulting Li(Ni0.96Co0.04)0.985Al0.01Nb0.005O2 (NCAN) cathode exhibits superior cycling stability, with a capacity retention of 77.8% after 300 cycles, even when operating at a high-voltage of 4.4V, outperforming the NC (48.5%). This work provides a promising perspective for developing high-voltage and high-Ni cathode materials.

Revealing Dynamic Evolution of the Anode‐Electrolyte Interphase in All‐Solid‐State Batteries with Excellent Cyclability

AbstractAll‐solid‐state‐batteries (ASSBs) based on a halide solid electrolyte (SE) and a lithium‐metal based anode typically have poor cyclability without a buffer layer (such as Li3PS4 or Li6PS5Cl) to prevent the degradation reactions. Here excellent cycling stability of ASSB consisting of an uncoated single‐crystal LiNi0.8Co0.1Mn0.1O2 cathode and a Li3YCl6 (LYC) SE separator in direct contact with a Li‐In anode are demonstrated. Through a combination of electrochemical measurements, synchrotron micro‐X‐ray absorption and diffraction analyses, and density functional theory calculations, reveal for the first time that along with the standard Li+ transport during charge/discharge, indium in the Li‐In anode also participates in the redox reactions. The in‐situ generated In3+ preferentially occupies the vacant Li sites in the trigonal LYC lattice, leading to the formation, growth, and eventual stabilization of an anode‐electrolyte interphase (AEI) layer consisting of an In‐doped Li3‐xInxYCl6 (x = ≈0.2) phase. It is discussed how the presence of such an AEI layer prevents LYC decomposition and suppresses dendrite formation and propagation, enabling stable cycling of ASSB with ≈90% capacity retention over 1000 cycles. This work sheds light on the dynamic evolution of the halide SE and alloy anode interphase, and opens new avenues in the future design of long‐lasting high‐energy all‐solid‐state‐batteries.

Quenching-Induced Ultrathin LiF-Rich Interphases on LiNi0.8Co0.1Mn0.1O2 Cathode

Nickel-rich layered oxides (NCM) are a promising contender material for the cathode electrode of high-energy lithium-ion batteries (LIBs) due to their large reversible capacity and high operating voltage. However, the poor surface/interfacial stability and the dissolution of transition metal ions hinder the commercial application of NCM. To create an artificial cathode electrolyte interphase (CEI) with LiF-rich inorganic phase on the NCM surface, a practical and efficient way of quenching the NCM powder from high temperature in 1,1,2,2-Tetrafluoroethyl 2,2,2-trifluoroethyl ether (HFE) was devised. With this artificial CEI film, the side reactions between NCM and electrolytes are inhibited, and the dissolution of TM ions is retarded. The quenched-NCM achieved fantastic cycling performance and suppressed voltage decay. Our research offers an efficient and worthy approach for improving the surface/interfacial stabilization of nickel-rich cathode materials for high-energy-density LIBs.

Effect of Subtle Changes in Ni2+/Ni3+ and Particle Surface Area in LiNi0.5Mn0.5−xCoxO2 (x = 0.1–0.3) Cathode Materials for Lithium-Ion Batteries

In Li[Ni,Mn,Co]O2 (NMC) cathode materials, small changes in transition metal ratio and particle surface area can significantly impact capacity retention. To understand the combined effect of transition metal ratio and the particle surface area, we studied LiNi0.5Mn0.5−xCoxO2 (x = 0.1–0.3) particles with two different morphologies: dense, spherical particles and high-surface area aggregates. All compositions in this series contain the same percentage of Ni but have differing amounts of Ni2+ and Ni3+. While Ni2+ tends to induce anti-site defects predominantly in the bulk, Ni3+ promotes particle surface reconstruction, both of which negatively impact capacity retention. Upon cycling to 4.4 V for 100 cycles, we observe that particles of high surface area with high Ni3+ concentration undergo the most severe capacity degradation. However, high surface area particles with high proportion of anti-site defects undergo sluggish capacity fade. Overall, with 60% of Ni2+ and 40% of Ni3+, spherical NMC 532 particles endure the detrimental effects of anti-site defects and surface reconstruction, but neither too prominently and thus emerges as the best candidate among the studied samples. This study highlights the synergy between transition metal ratio and particle surface area and how it determines the properties of the NMC cathode materials.

Stabilizing the bulk phase and interface of layered oxide cathode through Li&B double doping

Layered oxide cathodes have attracted widespread attention due to their high-voltage and high discharge capacity. Nevertheless, the irreversible redox reactions of layered oxide cathode and decomposition of electrolyte at high-voltage greatly reduce the reversibility of the batteries. Herein, we employ a double-doping (Li&B) strategy to enhance the electrochemistry performance of the layered NaNi0.3Fe0.3Mn0.4O2 (NNFM) cathode at high voltage. It proved that the dissolution of the transition metal can be restricted by double doping, and the irreversible phase transition is mitigated even at high voltage. As a result, battery with the double-doping cathode exhibits excellent electrochemistry performance, which achieves a capacity of 175 mAh g−1 at 0.2C, maintaining a capacity retention of approximately 87.3% over 100 cycles at 1C, and demonstrates exceptional rate performance. This work presents a novel insight into the doping technique for the high-performance cathode materials and offers a general method for the high energy Na-ion batteries.

Comparative study on the thermal runaway characteristics of Li(NixCoyMnz)O2 batteries

Lithium-ion batteries (LIBs) generate substantial gas during the thermal runaway (TR) process, presenting serious risks to electrochemical energy storage systems in case of ignition or explosions. Previous studies were mainly focused on investigating the TR characteristics of Li(NixCoyMnz)O2 batteries with different cathode materials, but they were conducted in isolation. In this study, the thermal runaway characteristics of prismatic cells that use Li(NixCoyMnz)O2 (with x ranging from 0.33 to 0.9) cathode materials in an inert environment, which are commonly used or proposed for energy storage applications, are examined. The findings of this research show that the normalized gas generation rate remains consistent, regardless of the battery capacity or experimental chamber volume, with a value of 0.1 ± 0.03 mol∙Ah⁻1. High-capacity cells have short jetting durations, and a high nickel content leads to increased mass loss rates. The flammability limits of the gases expelled during thermal runaway, represented by the lower flammability limit (LFL), remain stable at 8 ± 1.8 % with minimal variations. However, the upper flammability limit (UFL) varies significantly, ranging from 30 % to 60 %. Increasing the battery capacity or reducing the experimental chamber volume increases the explosion index. The explosive, combustibility, and jetting duration characteristics of the emitted gases from five different battery chemical compositions provide valuable insights for risk assessment in future electrochemical energy storage systems.

Comparison of lithium sources on the electrochemical performance of LiNi0.5Mn1.5O4 cathode materials for lithium-ion batteries

In order to fulfill the demand for high energy and capacity, an electrode with high-voltage capability, namely LiNi0.5Mn1.5O4 (LNMO) that has an operating potential of up to 4.7 V vs Li/Li+, is currently becoming popular in Li-ion battery chemistries. This research produced LNMO by using a solid-state method with only one-step synthesis route to compare its electrochemical performance with different lithium sources, including hydroxide (LNMO-LiOH), acetate (LNMO-LiAce), and carbonate (LNMO-LiCar) precursors. TGA/DSC was first performed for all three sample precursors to ensure the optimal calcination temperature, while XRD and SEM characterized the physical properties. The electrochemical measurements, including cyclic voltammetry and charge-discharge, were conducted in the half-cell configurations of LNMO//Li-metal using a standard 1 M LiPF6 electrolyte. LNMO-LiOH samples exhibited the highest purity and the smallest particle size, with values of 93.3% and 418 nm, respectively. In contrast, samples with higher impurities, such as LNMO-LiCar, mainly in the form of LixNi1-xO (LiNiO), displayed the largest particle size. The highest working voltage possessed by LNMO-LiOH samples was 4.735 V vs Li/Li+. The results showed that LNMO samples with LiNiO impurities would affect the reaction behavior that occurs at the cathode-electrolyte interface during the release of lithium-ions, resulting in high resistance at the battery operations and decreasing the specific capacity of the LNMO during discharging. The highest value, shown by LNMO-LiOH, was up to 92.75 mAh/g. On the other side, LNMO-LiCar only possessed a specific capacity of 44.57 mAh/g, indicating a significant impact of different lithium sources in the overall performances of LNMO cathode.

Surface Modification of High Voltage Spinel LiNi0.5Mn1.5O4 Cathode Material Manufactured via Co-precipitation

Spinel-structured LiNi0.5Mn1.5O4 (LNMO) can provide high energy density due to its high operating voltage of 4.7 V. LNMO materials synthesized through co-precipitation are suitable for commercialization because of their easily controllable particles and structure. However, their practical application is difficult due to electrolyte and surface-side reactions. In this study, TiO2 was coated with LNMO using the sol–gel method to evaluate its electrochemical properties and thermal stability. Consequently, the TiO2 coating improved the rate performance and long-term battery cycling. Additionally, the cycling characteristics at high temperatures were improved by enhancing the thermal stability of the charged LNMO particles.