Lithium-rich Manganese-based Cathode Research Articles

State-of-Charge Estimation of Lithium-Rich Manganese-Based Batteries Based on WOA LSTM and Extended Kalman Filter

Recent years, electric vehicles gradually become popular, but their cruising range has become one of the main problems that plague car companies and users. The lithium-rich manganese-based cathode material batteries with higher energy density stand out. The state of charge is an important parameter. This paper selects a 19Ah lithium-rich manganese-based cathode material battery for research, using extended Kalman filter based on second-order Equivalent circuit model estimate its state of charge. However, the impedance spectrum of lithium-rich manganese battery is different from that of 18650 lithium-ion battery, and the second-order equivalent circuit model will have errors, resulting in the low accuracy of SOC estimation. In order to solve this problem, this paper proposes two schemes: EKF-LSTM and LSTM-EKF. The whale optimization algorithm (WOA) is used to select the preset parameters. The results show that the LSTM-EKF method has the highest estimation accuracy, with a maximum error of 1.46%.

Efficient recovery and utilization of electrolytic manganese anode mud- preparation of high-performance Li1.2Ni0.2Mn0.6O2 cathode material for lithium-ion batteries

The booming electrolytic manganese industry has brought a huge amount of electrolytic manganese anode mud (EMAM). The management and value-added recovery of EMAM were very important for environmental improvement and economic benefits. In this study, EMAM is used as a cost-effective raw material. Firstly, the manganese-containing solution was obtained by reducing acid leaching with EMAM. Then, Li1.2Ni0.2Mn0.6O2 (Z-LNMO) cathode materials were prepared from a manganese-containing solution by co-precipitation process. Finally, to enhance the performance of the Z-LNMO materials, surfactants (C12H25SO4Na, C10H14N2Na2O8, C18H29NaO3S, C19H42BrN) were introduced in the preparation of precursor materials to obtain the material with higher crystallinity. ICP results showed that S/Fe ions of EMAM were retained in Z-LNMO materials. Moreover, the Z-LNMO sample shows a stoichiometric similar element content to Li1.2Ni0.18Fe0.02Mn0.6O1.96S0.04. EDS results show that S/Fe ions were uniformly distributed in Z-LNMO materials. The shift of XRD peak further indicates that the use of EMAM waste is expected to directly obtain S/Fe ions doped lithium-rich manganese-based cathode materials. The first-principle calculation shows that the S/Fe ions as the doping source make the transfer of excited electrons from the valence band to the conduction band easier, thereby enhancing the conductivity of the materials. The CV curve and differential capacity (dQ/dV) curve show that the Z-LNMO material prepared by EMAM inhibits the excessive oxidation of Li2MnO3 to a certain extent, thus providing excellent reversible capacity and stabilizing the material structure. Electrochemical evaluation reveals that the Z-LNMO materials prepared with the EMAM exhibit superior cycling stability (112% after 100 cycles at 0.1C). Moreover, the introduction of C10H14N2Na2O8 (EDTA-2Na) and C12H25SO4Na (SDS) in the preparation of precursor materials can improve the first discharge-specific capacity and stability of materials by modifying the morphology of precursor materials (refine particles). Among them, the materials modified by EDTA-2Na show the best performance, and the particle size is about 200 nm. Compared with the original materials, the improved first discharge-specific capacity (218.6 mAh g−1 at 0.1C) and capacity retention (245.8 mAh g−1 after 100 cycles) of the materials modified with EDTA-2Na were improved. The EIS results also confirm that the introduction of EDTA-2Na effectively decreases the charge transfer resistance and facilitates the Li diffusion of the as-prepared cathode materials. This work confirmed the possibility of extracting manganese from EMAM to prepare lithium-rich manganese-based cathode materials, and provided a new promising way for the efficient value-added utilization of EMAM.

A 700 W⋅h⋅kg−1 Rechargeable Pouch Type Lithium Battery

High-energy-density rechargeable lithium batteries are being pursued by researchers because of their revolutionary potential nature. Current advanced practical lithium-ion batteries have an energy density of around 300 W⋅h⋅kg−1. Continuing to increase the energy density of batteries to a higher level could lead to a major explosion development in some fields, such as electric aviation. Here, we have manufactured practical pouch-type rechargeable lithium batteries with both a gravimetric energy density of 711.3 W⋅h⋅kg−1 and a volumetric energy density of 1653.65 W⋅h⋅L−1. This is achieved through the use of high-performance battery materials including high-capacity lithium-rich manganese-based cathode and thin lithium metal anode with high specific energy, combined with extremely advanced process technologies such as high-loading electrode preparation and lean electrolyte injection. In this battery material system, the structural stability of cathode material in a widened charge/discharge voltage range and the deposition/dissolution behavior of interfacial modified thin lithium electrode are studied.

Boosting the kinetic properties and suppressing the irreversible oxygen redox of lithium-rich manganese-based cathode materials through combined strategies of fast ionic conductor and oxygen vacancy

Oxygen-anion charge compensation facilitates lithium-rich manganese-based cathode materials (LRMCs) to possess higher specific capacity than other conventional layered oxide cathode materials. Nevertheless, irreversible oxygen redox makes LRMCs suffer from oxygen loss, structure degradation, and interfacial side reactions and thus resulting in low initial coulombic efficiency (ICE), poor cyclic stability and rate capacity. To inhibit the irreversible anionic redox and improve the kinetic properties of Li1.2Mn0.54Ni0.13Co0.13O2 (LMNCO), herein, an interfacial engineering with sodium hypophosphite (NaH2PO2) is used to modify the LMNCO. The results demonstrate that the Na2HPO4 and reducing gas PH3 that are produced by NaH2PO2 decomposition can react with the residual lithium and unstable surface oxygen to form a stable Li3PO4 protective layer and generate oxygen vacancies on the LMNCO surface. It has been found that the optimum content of NaH2PO2 is 5 wt%, and the electrochemical performance of LMNCO-NP 5% is significantly improved. The ICE of LMNCO-NP 5% is 82.79%, which is much higher than the LMNCO (73.76%). Meanwhile, the capacity retentions of LMNCO-NP 5% are 94.85% and 78.45% at 1 C and 5 C after 100 cycles, respectively. Therefore, the modification strategy based on the formation of Li3PO4 protective layer and generation of oxygen vacancies can play effectively promote the electrochemical performances of LMNCO.

Enhancing cyclic performance of lithium-rich manganese-based cathode via in-situ co-doping of magnesium and fluorine

Lithium-rich manganese-based materials (LRM) are regarded as promising next-generation commercial cathodes due to their exceptionally high capacities and working voltages. However, lithium-rich manganese-based materials are plagued with inferior cyclic stability and voltage fading, which greatly stifled their commercial transitions. In this work, the dopant F and Mg uniformly distributed lithium-rich manganese-based cathode material is firstly prepared via an in-situ co-precipitation and high-temperature calcination method. The F and Mg co-doped sample can demonstrate excellent cyclic stability (88.56%, after 100 cycles at 1 C), and higher initial discharge and coulombic efficiency by reducing the transition metal (TM) loss and structure stabilization. Thus, this work presents crucial findings in the development of lithium-rich manganese-based materials, which provides a novel doping route and a vital method of cation-anion co-doping to prepare high-performing cathodes.

Construction of Lithium-Rich Manganese-Based Cathodes Based on Activated Manganese Dioxide for Enhanced Energy Storage Performances

Herein, highly active manganese dioxide is prepared by roasting-disproportionation treatment to fabricate a lithium-rich manganese-based cathode (Li1.6Mn0.6Ni0.3Co0.1O2.6) for enhanced charge/discharge capacity performance. The findings display that the roasting temperature and subsequent disproportionation degree significantly affect crystalline structure of manganese dioxide, thereby apparently improving the electrochemical performances of lithium-rich manganese-based cathodes. When the roasting temperature is 600 °C, the content of α-MnO2 reaches to 69.3% in lithium-rich manganese-based cathode, resulting in the best electrochemical activity. The prepared lithium-rich cathode material displays a discharge capacity of 243 mAh/g after 100 cycles at 0.2 C, and 155 mAh/g at 3 C, which shows good multiplicative performance.

Enabling stable 4.6 V LiCoO2 cathode through oxygen charge regulation strategy

LiCoO2 is the preferred cathode material for consumer electronic products due to its high volumetric energy density. However, the unfavorable phase transition and surface oxygen release limits the practical application of LiCoO2 at a high-voltage of 4.6 V to achieve a higher energy density demanded by the market. Herein, both bulk and surface structures of LiCoO2 are stabilized at 4.6 V through oxygen charge regulation by Gd-gradient doping. The enrichment of highly electropositive Gd on LiCoO2 surface will increase the effective charge on oxygen and improve the oxygen framework stability against oxygen loss. On the other hand, Gd ions occupy theCo-sites and suppress the unfavorable phase transition and micro-crack. The modified LiCoO2 exhibits superior cycling stability with capacity retention of 90.1% over 200 cycles at 4.6 V, and also obtains a high capacity of 145.7 mAh/g at 5 C. This work shows great promise for developing high-voltage LiCoO2 at 4.6 V and the strategy could also contribute to optimizing other cathode materials with high voltage and large capacity, such as cobalt-free high-nickel and lithium-rich manganese-based cathode materials.

Aluminum doping and lithium tungstate surface coating double effect to improve the cycle stability of lithium-rich manganese-based cathode materials

Al doped lithium-rich manganese-based Li1.2Mn0.54−xAlxNi0.13Co0.13O2 (x = 0, 0.03) cathode materials for lithium-ion batteries were synthesized with sol-gel method, and then Li2WO4 coating was prepared by one-step liquid phase method. The effects of Al doping and Li2WO4 coating on the electrochemical properties of lithium-rich manganese-based cathode materials were systematically studied. The results show that Al doping significantly improves the cycle stability of lithium-rich manganese-based cathode material, and the coating Li2WO4 significantly improves its magnification performance and the voltage attenuation of discharge plateau. The coating amount of Li2WO4 is 5%, and the specific capacity of Li1.2Mn0.51Al0.03Ni0.13Co0.13O2 cathode material is still up to about 110 mAh·g−1 in the charge and discharge voltage range of 2.0-4.8 V and the current density of 1,000 mA·g−1. At the same time, the capacity retention rate of 300 cycles at the current density of 100 mA·g−1 is 78%, and the voltage attenuation of the discharge plateau during the cycle is also significantly reduced. This work provides a new idea for solving the cycle stability and platform voltage attenuation of lithium-ion battery lithium-rich manganese-based cathode materials.

Surface engineering for high stable lithium-rich manganese-based cathode materials

Lithium-rich manganese-based material shows great potential as the high specific cathode materials due to its low cost, environmental friendliness, high operating voltage and simple preparation process. However, the poor capacity retention and cycling performance caused by its unstable structure during cycling restrict the commercialization. In this work, Li1.2Ni0.16Mn0.56Co0.08O2 was synthesized utilizing a Co-precipitation method and different amount of La(PO3)3 (La(PO3)3 = 2 wt%, 4 wt% and 6 wt%) was selected as the coating layer to resolve the above issues. During the calcination process, La(PO3)3 reacts with impurities such as LiOH and Li2CO3 on the lithium-rich surface to reduce the residual lithium on the surface, thus improving the interfacial stability, slowing down the corrosion of the electrolyte, and finally enhancing its electrochemical performance. The cathode materials coated with 4% of La(PO3)3 showed the best electrochemical performance in terms of capacity retention and cycling performance compared to the pristine NCM. The high initial discharge capacity of 214.21 mAh/g and capacity retention of 94.2% after 100 cycles at 0.1 C can be obtained. This work provides an effective strategy to protect the cathode from corrosion and will promote its further practical applications in high specific Li-ion batteries.

Suppress oxygen evolution of lithium-rich manganese-based cathode materials via an integrated strategy

Improving the reversibility of anionic redox and inhibiting irreversible oxygen evolution are the main challenges in the application of high reversible capacity Li-rich Mn-based cathode materials. A facile synchronous lithiation strategy combining the advantages of yttrium doping and LiYO2 surface coating is proposed. Yttrium doping effectively suppresses the oxygen evolution during the delithiation process by increasing the energy barrier of oxygen evolution reaction through strong Y–O bond energy. LiYO2 nanocoating has the function of structural constraint and protection, that protecting the lattice oxygen exposed to the surface, thus avoiding irreversible oxidation. As an Li+ conductor, LiYO2 nanocoating can provide a fast Li+ transfer channel, which enables the sample to have excellent rate performance. The synergistic effect of Y doping and nano-LiYO2 coating integration suppresses the oxygen release from the surface, accelerates the diffusion of Li+ from electrolyte to electrode and decreases the interfacial side reactions, enabling the lithium ion batteries to obtain good electrochemical performance. The lithium-ion full cell employing the Y-1 sample (cathode) and commercial graphite (anode) exhibit an excellent specific energy density of 442.9 Wh kg−1 at a current density of 0.1C, with very stable safety performance, which can be used in a wide temperature range (60 to −15 °C) stable operation. This result illustrates a new integration strategy for advanced cathode materials to achieve high specific energy density.

Xanthan gum with double-helix structure as a novel aqueous binder to stabilize lithium-rich cathode

Lithium-rich manganese-based cathode materials have the advantages of high specific capacity and operating voltage, but they still pose some problems such as poor cycle performance and serious voltage fading. Here, xanthan gum (XG) with double-helix structure has been investigated as a novel aqueous binder to improve the electrochemical performance of Li[Li0.2Co0.13Ni0.13Mn0.54]O2. When the mass proportion of XG is 5%, the prepared lithium-rich cathode shows the highest specific capacity and best cycle stability. After cycling, the discharge voltage of the lithium-rich cathode decreases by only 273 mV, indicating that XG can effectively inhibit the voltage fading of the lithium-rich material.

Inhibiting Mn Migration by Sb-Pinning Transition Metal Layers in Lithium-Rich Cathode Material for Stable High-Capacity Properties.

Owing to the interacted anion and cation redox dynamics in Li2 MnO3 , the high energy density can be obtained for lithium-rich manganese-based layered transition metal (TM) oxide [Li1.2 Ni0.2 Mn0.6 O2 , LNMO]. However, irreversible migration of Mn ions and oxygen release during highly de-lithiation can destroy its layered structure, leading to voltage and capacity decline. Herein, non-TM antimony (Sb) is pinned to the TM layer of LNMO by a facile sol-gel method. High-resolution ex and in situ characterization technologies manifest that the introduction of trace Sb inhibits the migration of Mn ions, forming a more stable structure. Sb can impressively adjust the Mn-O interaction between anions and cations, beneficial to decrease the energy level of Mn 3d and O 2p orbitals and expand their band gap according to the theoretical calculation results. As a result, the discharge specific capacity and the energy density for SbLi1.2 [Ni0.2 Mn0.6 ]O2 (SLNMO) reaches as high as 301 mAh g-1 and 1019.6Wh kg-1 at 0.1 C, respectively. Moreover, the voltage decay is reduced by 419.8mV compared with LNMO. The regulative interaction between Mn 3d and isolated O 2p bands provides an accurate guidance for solving electrochemical performance deficiencies of lithium-rich manganese-based cathode oxide.

Suppressing Surface Lattice Oxygen Evolution by Fluorinated Graphene-Scaffolded Lithium-Rich Manganese-Based Cathode for Enhanced Stability

Li-rich manganese-based layered oxides (LRMLO) have aroused widespread concern because of their much higher theoretical specific capacity than conventional cathode materials. However, unsuppressed lattice oxygen evolution brings about critical issues such as layer-to-spinel phase transition and oxygen release, extremely restricting their practical implementation. Herein, a fluorinated graphene-scaffolded LRMLO (LRMLO@FG) is prepared to effectively promote the oxygen redox stabilization and suppress lattice oxygen evolution. The investigations on oxygen redox couple (O2−/On–, n < 2) and manganese electronic structure illustrated that LRMLO@FG electrode preserved more lattice oxygen (O2−) and Mn4+ accounted for a higher proportion of total manganese after cycling, which were ascribed to the increase of the formation energy of oxygen vacancy and the reinforcement of Mn-O bond as suggested by DFT calculations. Furthermore, in situ XRD characterization demonstrated the lattice spacing of LRMLO@FG electrode was well restored to the original value, indicating that FG promoted the reversibility of crystal structure transition and the oxygen redox stabilization during the lithiation-delithiation process. The LRMLO@FG||Li cell exhibits greatly improved cycling stability with capacity retention of 88 % after 100 cycles and more stable Coulombic efficiency. This work offers an effective method to overcome the intrinsic challenges of LRMLO towards practical and high-energy lithium-ion batteries.

Study on La-doped lithium-rich manganese-based cathode materials (Li1.5Mn0.7Co0.15Ni0.15O2.5)

Study on La-doped lithium-rich manganese-based cathode materials (Li1.5Mn0.7Co0.15Ni0.15O2.5)

A facile and high-effective oxygen defect engineering for improving electrochemical performance of lithium-rich manganese-based cathode materials

The irreversible evolution of oxygen for lithium-rich manganese-based cathode (LRMC) is the main challenge which will induce accelerated migration of transition metal ions and structural transformation, thus resulting in serious voltage attenuation and capacity decay. Herein, a facile and high-effective oxygen vacancy engineering of hydrogenation treatment is proposed for introducing oxygen vacancy on the surface of LRMC to suppress the irreversible evolution of oxygen. X-ray diffraction (XRD) Rietveld refinement, X-ray photoelectron spectroscopy and electron paramagnetic spectroscopy demonstrate the successful introduction of oxygen vacancy on the surface of LRMC. The changes of physicochemical properties of LRMC after hydrogenation treatment are investigated through systematical electrochemical performance tests and scanning electron microscopy and transmission electron microscopy. The investigative results reveal that the presence of oxygen vacancy can significantly improve the structural stability, electrical conductivity and Li+ diffusion kinetics of the LRMC materials. Especially, the optimized H500-LRMC shows excellent electrochemical performances including the enhanced cyclic stability with a capacity retention of 221.8 mAh g−1 and a capacity retention rate of 94.11% after 100 cycles. Therefore, the well-designed oxygen vacancy engineering through hydrogenation treatment is a promising strategy for the development and industrialization of the high-performance LRMC.

Improvement of electrochemical properties of lithium-rich manganese-based cathode materials by Ta2O5

Improvement of electrochemical properties of lithium-rich manganese-based cathode materials by Ta2O5

One-pot synthesis and multifunctional surface modification of lithium-rich manganese-based cathode for enhanced structural stability and low-temperature performance

High-energy–density lithium-rich Li1.2Ni0.13Co0.13Mn0.54O2 is regarded as one of the most promising cathode materials for lithium-ion batteries. However, its practical application is restricted by critical kinetics drawbacks and poor low-temperature electrochemical performances. In this research, Li1.2Ni0.13Co0.13Mn0.54O2 submicron particles coated by a Li7La3Zr2O12 (LLZO) layer and co-doped by La/Zr cations has been fabricated via a facile one-pot sol–gel technique and subsequent heat treatment. The coating LLZO layer with a few nanometers is able to build a rapid lithium-ion transport channel for adjacent particles and suppress severe side reactions between active material and the electrolyte. Moreover, large-radius La/Zr cations co-doping can broaden the diffusion paths of lithium ions, hinder the detrimental structural transformation, and improve the electrochemical structure stability of the cathode during repeated cycles. Owing to numerous merits from this multifunctional surface modification strategy, the modified Li1.2Ni0.13Co0.13Mn0.54O2 composite exhibits the significantly decreased interface impedance, enhanced Li+ diffusion kinetics and mitigated phase transformation, as well as excellent low-temperature electrochemical performance. It can contribute ultrahigh capacities of 173.8 mAh g−1 at −10 ℃ and 134.1 mAh g−1 at −20 ℃, respectively, displaying great application prospects of Li-rich cathode materials.

Effects of Triple Modification Of Sodium Hypophosphite on Structure and Electrochemical Performances of Lithium-Rich Manganese-Based Cathode Materials

Effects of Triple Modification Of Sodium Hypophosphite on Structure and Electrochemical Performances of Lithium-Rich Manganese-Based Cathode Materials

Multi-dimensional correlation of layered Li-rich Mn-based cathode materials

Lithium-rich manganese-based cathode materials are expected to promote the commercialization of lithium-ion batteries to a new stage by virtue of their ultrahigh specific capacity and energy density advantages. However, they are still restricted by complex phase transitions and electrochemical performance degradation caused by labile anion charge compensation. A deep understanding of the electrochemical properties contained in their intrinsic structures and the key driving factors of structural deterioration during cycling are crucial to guide the preparation and optimization of lithium-rich materials. Considering recent progress, this review introduces the intrinsic properties of Li-rich manganese-based cathode materials from interatomic interactions to particle morphology at multiple scales in the spatial dimension. The charge compensation mechanism and energy band reorganization of the initial charge and discharge, the structural evolution during cycling and the electrochemical reaction kinetics of the materials are analyzed in the temporal dimension. Based on the relationship between structure and electrochemical performance, preparation methods and modification methods are introduced to guide and design cathode materials. Effective characterization methods for studying anion charge compensation behavior are also demonstrated. This review provides important guidance and suggestions for making full use of the high specific capacity in these materials derived from anion redox and the maintaining of its stability.

Suppressing Surface Lattice Oxygen Evolution by Fluorinated Graphene-Scaffolded Lithium-Rich Manganese-Based Cathode for Enhanced Stability

Suppressing Surface Lattice Oxygen Evolution by Fluorinated Graphene-Scaffolded Lithium-Rich Manganese-Based Cathode for Enhanced Stability