LiCoO2 Cathode Materials Research Articles

Study of Pr doped nanocrystalline LiCoO2 cathode material for spintronic and energy storage applications: A theoretical and experimental analysis

In this study, Pr3+ substituted LiCoO2 lithium-rich cathode materials were prepared using the sol-gel auto-combustion technique to enhance cycling performance. LiCo1-xPrxO2 samples having Pr concentrations x = 0.00–0.10 were synthesized. X-ray diffraction (XRD) showed a rhombohedral structure with space group R-3m, further verified by the Rietveld refinement. Field emission scanning electron microscopy (FESEM) revealed the presence of distinct and well-defined submicron-scale grains. FTIR spectroscopy confirmed Co–O stretching bonds within 590–560 cm−1 and revealed peaks at around 560–590, 830–860, and 1320-1480 cm−1, which could be attributed to the electrochemical performance of Pr-doped species. Moreover, EDX spectroscopy confirmed the typical elemental peaks of only Co, Pr, and O, confirming the required phase presence. The cyclic voltammetry showed improved reversibility and stability due to Pr doping. The first-principles computations were performed using the lattice constant extracted from XRD measurements. The pure LiCoO2 with a semiconducting nature became half-metallic due to Pr doping (LiCo0.84Pr0.16O2). The magnetic properties indicate that LiCoO2 and LiCo0.84Pr0.16O2 exhibit positive magnetic order, which shows that these are suitable candidates for spintronic applications. The pure LiCoO2 revealed intercalation voltages of 4.10–2.73V and a theoretical capacity 40–203 mAh/g. Meanwhile, for LiCo0.84Pr0.16O2, the intercalation voltages and theoretical capacity improved to 4.42–2.85 V and 42 to 211 mAh/g, respectively. The combined experimental and theoretical study suggests that Pr-doped LiCoO2 is suitable for spintronic applications and energy applications such as composite cathodes.

Imaging in-operando LiCoO2 nanocrystallites with Bragg coherent X-ray diffraction

Although the LiCoO2 (LCO) cathode material has been widely used in commercial lithium ion batteries (LIB) and shows high stability, LIB’s improvements have several challenges that still need to be overcome. In this paper, we have studied the in-operando structural properties of LCO within battery cells using Bragg Coherent X-ray Diffraction Imaging to identify ways to optimise the LCO batteries’ cycling. We have successfully reconstructed the X-ray scattering phase variation (a fingerprint of atomic displacement) within a ≈ (1.6 × 1.4 × 1.3) μm3 LCO nanocrystal across a charge/discharge cycle. Reconstructions indicate strained domains forming, expanding, and fragmenting near the surface of the nanocrystal during charging, with a determined maximum relative lattice displacements of 0.467 Å. While discharging, all domains replicate in reverse the effects observed from the charging states, but with a lower maximum relative lattice displacements of 0.226 Å. These findings show the inefficiency-increasing domain dynamics within LCO lattices during cycling.

Fabrication of High-performance LiCoO2 Cathode Materials by Regulated Resource Regeneration from Spent Lithium-Ion Batteries

Fabrication of High-performance LiCoO2 Cathode Materials by Regulated Resource Regeneration from Spent Lithium-Ion Batteries

Ionic-conductive poly (vinylidene fluoride) polymer as a versatile binder to stabilize high-voltage LiCoO2 cathode materials

Ionic-conductive poly (vinylidene fluoride) polymer as a versatile binder to stabilize high-voltage LiCoO2 cathode materials

Multi-element synergistic doping enhances high-voltage performance of LiCoO2 via stabilizing internal and surface structures

With the escalating commercialization of 5 G technology and the constant emergence of novel electronic devices, the demand for energy density of LiCoO2 cathode material has been on a consistent rise. Boosting the upper cut-off voltage is an essential approach for enhancing the energy density. While the high-voltage environment facilitates adverse side reactions like irreversible phase transition and electrolyte degradation, thereby accelerating battery capacity degradation. Herein, a straightforward and efficient high-temperature solid-phase strategy is utilized and the elements Ba, Mg, Ga, and Ti are selected for trace doping. Our findings reveal positive synergistic effects among these elements. Mg and Ga significantly suppress the arising of oxygen ligand holes. The distinct distribution of Mg and Ba balances and improves the electronic conductivity inside the elementary particles. Additionally, a triple control system of Ba, Mg, and Ga highlights the important role of Ti. Advanced characterization methods confirm that this approach reduces the particle radius and enhances rapid charging and discharging capabilities of the cathode material. What's more, it effectively suppresses harmful phase transitions and side reactions, maintaining the structure stability. Within the range of 3–4.6 V, the discharge specific capacity reaches 188 mAh/g after 100 cycles, with a capacity retention of 86 %. Furthermore, it demonstrates outstanding rate performance, achieving a specific capacity of 104 mAh/g at 10 C. This improved electrochemical performance underscores the benefits of the synergistic strategy utilizing Ba, Mg, Ga, and Ti, providing a novel approach for developing high-performance LiCoO2 materials.

Comprehensive recovery of valuable metals from spent LiCoO2 cathode material by a method of NH4HSO4 roasting- (NH₄)₂S leaching

With the retirement of rechargeable lithium-ion batteries (LIBs) entering peak period, the recycling of LiCoO2 has become a hot topic. The spent LiCoO2 batteries are rich in carcinogenic metal Co and high-value metal Li, so they are needed to be recovered in time before causing serious environmental pollution and resource waste. Thus, a clean and efficient process is proposed for the comprehensive recovery of Li, Co, and Mn from the spent LiCoO2 cathode material. It is an integrated pyro-hydrometallurgical process, mainly consisting of sulfation roasting with NH4HSO4 and selective sulfurizing leaching with (NH4)2S solution. Using low melting point ammonium salt as roasting auxiliary, 99.7 %, 99.1 %, and 99.8 % of Li, Co, and Mn in the spent LiCoO2 powder can be converted into sulfate when roasting under 400 ℃ for 75 min. Then 99.5 % of Li in the sulfation roasting product can be selectively leached with an aqueous (NH4)2S solution, which is also a precipitator for Co, Mn, and impurity Al. In addition, 96.4 % of Co and 96.0 % of Mn in the sulfurized precipitate can be separated with impurity elements Al and C via oxidation roasting–water leaching process. Compared to traditional recycling, this method can achieve a higher Li leaching rate at a low roasting temperature, and the recovery of Co and Mn can be realized without adding any acid/base reagents or impurity cations. More importantly, the circulation of NH3/NH4+ and S element in the recycling system has been taken into account, making it an environmental-friendly and economical process. In this study, the sulfation reduction roasting and selective sulfurizing leaching mechanisms were both revealed in details, and the behavior of the valuable elements was also elucidated.

Holistic view on cation interdiffusion during processing and operation of garnet all-solid-state batteries

All-solid-state batteries based on the active cathode material LiCoO2 (LCO), a garnet-type Li7La3Zr2O12 (LLZO) electrolyte and a Li-metal anode are attracting a lot of attention as a robust and safe alternative to conventional lithium-ion batteries. The challenges in the practical realization of such cells are related to high-temperature sintering, which compacts the ceramic powder but also leads to undesirable material interactions such as cation interdiffusion and secondary phase formation. Even if high initial capacities can be achieved, the all-inorganic cells suffer from a strong capacity drop due to various degradation phenomena during processing and operation, which are not yet fully understood. In this study, the thermodynamic and kinetic aspects of co-sintering as well as the structural evolution of materials and interfaces during processing and operation of co-sintered LCO-LLZO cathodes are investigated in detail. A thermodynamic model for the interdiffusion of cations is derived and the effects of the diffusion of Al- and Co-ions, which occurs during the processing and cycling of the cells, are investigated. In LLZO, the diffusion of 0.13 Co per formula unit (pfu) has a negligible effect on ionic and electronic conductivity and electrochemical stability. In contrast, the substitution of 0.01 pfu Al and the induced disorder in the layer structure of LCO increases the polarization during cycling. All-inorganic cells fabricated with optimized sintering parameters to minimize interdiffusion between LCO and LLZO show good initial performance but similar degradation during cycling, as the used processing parameters result in a more porous microstructure leading to the development of cracks along the LLZO/LCO interface. The results obtained highlight the inherent instabilities of all-ceramic cathodes with unprotected LCO/LLZO interfaces, which require precise tuning of materials and processing parameters to achieve both high mechanical stability and low interdiffusion.

High-Voltage Long-Cycling All-Solid-State Lithium Batteries with High-Valent-Element-Doped Halide Electrolytes.

All-solid-state batteries (ASSBs) have garnered considerable attention as promising candidates for next-generation energy storage systems due to their potentially simultaneously enhanced safety capacities and improved energy densities. However, the solid future still calls for materials with high ionic conductivity, electrochemical stability, and favorable interfacial compatibility. In this study, we present a series of halide solid-state electrolytes (SSEs) utilizing a doping strategy with highly valent elements, demonstrating an outstanding combination of enhanced ionic conductivity and oxidation stability. Among these, Li2.6In0.8Ta0.2Cl6 emerges as the standout performer, displaying a superionic conductivity of up to 4.47 mS cm-1 at 30 °C, along with a low activation energy barrier of 0.321 eV for Li+ migration. Additionally, it showcases an extensive oxidation onset of up to 5.13 V (vs Li+/Li), enabling high-voltage ASSBs with promising cycling performance. Particularly noteworthy are the ASSBs employing LiCoO2 cathode materials, which exhibit an extended cyclability of over 1400 cycles, with 70% capacity retention under 4.6 V (vs Li+/Li), and a capacity of up to 135 mA h g-1 at a 4 C rate, with the loading of active materials at 7.52 mg cm-2. This study demonstrates a feasible approach to designing desirable SSEs for energy-dense, highly stable ASSBs.

Synthesis Pathway of Layered-Oxide Cathode Materials for Lithium-Ion Batteries by Spray Pyrolysis.

We report the synthesis of LiCoO2 (LCO) cathode materials for lithium-ion batteries via aerosol spray pyrolysis, focusing on the effect of synthesis temperatures from 600 to 1000 °C on the materials' structural and morphological features. Utilizing both nitrate and acetate metal precursors, we conducted a comprehensive analysis of material properties through X-ray diffraction (XRD), Raman spectroscopy, thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). Our findings reveal enhanced crystallinity and significant oxide decomposition within the examined temperature range. Morphologically, nitrate-derived particles exhibited hollow, spherical shapes, whereas acetate-derived particles were irregular. Guided by high-temperature X-ray diffraction (HT-XRD) data, the formation of a layered LCO oxide structure, with distinct spinel Li2Co2O4 and layered oxide LCO phases was shown to emerge at different annealing temperatures. Optimally annealed particles showcased well-defined layered structures, translating to high electrochemical performance. Specifically, nitrate-based particles annealed at 775 °C for 1 h demonstrated initial discharge capacities close to 179 mAh/g, while acetate-based particles, annealed at 750 °C for 3 h, achieved 136 mAh/g at a 0.1C discharge rate. This study elucidates the influence of synthesis conditions on LCO cathode material properties, offering insights that advance high throughput processes for lithium-ion battery materials synthesis.

Correlative Survey of Blended LiCoO2 and LiMn2O4 Cathode Materials for Lithium-ion Batteries

We employed the lithium-ion battery model in Multiphysics to simulate the electrochemical characteristics of lithium-ion batteries. These batteries consist of a cathode mixture comprising LiCoO2 and LiMn2O4, as well as quasi-graphite anode. Our simulations successfully replicated the discharge profiles of both unblended and blended cathodes across different current rates, aligning with results obtained from experiments. The energy and power densities of the blended cathode framework were regulated by adjusting the mix ratio in the simulation model. Additionally, the blended electrodes of LiCoO2 and LiMn2O4 demonstrated an above-average electrochemical performance, combining the characteristics of the two active materials.Keywords: Lithium-ion Battery; Blended Cathode Active Materials; Simulation; Experiment

Recycling of LiCoO2 from the cathode of a waste lithium battery via reduction in a molten salt

A new method for recycling and resynthesizing a lithium battery cathode material was developed. A LiCl-KCl molten salt was used as a medium. The raw materials were LiOH·H2O obtained by membrane electrolysis and Co2O3 obtained by carbothermal reduction, and the high-performance cathode material LiCoO2 was synthesized by molten salt method, and then placed into a battery for recycling. The specific reaction process and reaction kinetics for the LiCoO2 synthesis were studied by TG-DSC thermal analyses. The effects of different reaction conditions on the structure and morphology of the LiCoO2 were studied by XRD and SEM. The battery performance of the LiCoO2 was characterized with electrochemical analyses. The activation energies of the three endothermic reactions occurring in the synthetic process were calculated with the Kissinger method and were 34.212 kJ·mol−1, 168.53925 kJ·mol−1 and 221.26181 kJ·mol−1. The experimental battery prepared from a LiCoO2 sample calcined at 720 °C for 7 h showed first charge–discharge specific capacities of 150 mAh/g and 147 mAh/g, and the coulombic efficiency was 98%. The discharge specific capacity after 50 charge and discharge cycles was still 129 mAh/g. The battery showed good charge and discharge performance after rate cycling.

Ultrasound-assisted sustainable recycling of valuable metals from spent Li-ion batteries via optimisation using response surface methodology

In this study, the use of response surface methodology was proposed to optimise a novel green leaching process for recovering Li and Co from spent lithium-ion batteries (LIBs), assisted by ultrasonic irradiation and gluconic acid. This work investigated various parameters such as temperature, time, gluconic acid concentration, and ultrasound power (US power). To enhance the interpretability and optimisation of experimental data on metal leaching, the central composed design (CCD) was utilised to establish a predictive model. A statistical analysis using the analysis of variance (ANOVA) test was conducted to validate the quadratic model and determine the significant operating parameters, indicated by p-values (< 0.05). The model exhibited Adj R2 values of 0.98 for Li leaching and 0.96 for Co leaching, respectively. To confirm the results, additional characterisations of the solid residues were performed using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Fourier transformation infrared spectrometer (FT-IR/NIR). The leach liquor was subjected to precipitation and crystallisation methods to recover Li and Co. The purity of Li2CO3 and Co3O4 was confirmed to be ≥ 99% and ≥ 98.8%, respectively, through ICP-OES analysis. Finally, the recovered Li2CO3 and Co3O4 were utilised in a 1:1 molar ratio for regenerating new LiCoO2 cathode materials using a solid-state method. The resulting cathode materials exhibited high purity (≥ 99.43%) as confirmed by ICP-OES analysis. The obtained results demonstrate that ultrasound irradiation significantly enhanced the dissolution of metal oxides within the mixture. Furthermore, gluconic acid exhibited a dual function, acting as both an oxidising and reducing agent. Consequently, this process presents a promising and sustainable alternative for recycling valuable metals from spent LIBs.

Separation of Li and Co From LiCoO2 Cathode Material Through Aluminothermic Reduction: Investigation of the Thermite Reaction

Aluminum can be used as a reductant for metal oxide reduction processes. This study investigates the reaction between Al with LiCoO2 in the context of recycling and separation of Li and Co from end-of-life battery cathode material. Specifically, this work attempts to investigate the initiation of the ignition of the thermite reaction. Both thermodynamic assessments and experimental work were carried out on the LiCoO2-Al system in the range of 750 °C to 1020 °C with three different amounts of Al additions in the sample, i.e., 11 wt pct, 20 wt pct, and 28 wt pct. It was found that the amount of Al (composition of the sample), the sample weight, and the initial heating temperature affect the occurrence of spontaneous ignition of the thermite reaction in the system leading to the partial/full melting of the sample. A function of Biot number and temperature was utilized to construct maps showing the onset of ignition where it was found that samples with large Biot numbers tend to ignite. In addition, higher Al addition, sample mass, and temperature were likely to generate ignition. The ignition was found to govern the type of end products of Li and Co; for example, the Li was distributed to gas as Li(g) and slag as LiAlO2 while Co could be extracted as Co metal or Co-Al alloy. The 11 wt pct and 20 wt pct Al addition to the samples resulted in a pure metallic cobalt product, whereas 28 wt pct Al addition resulted in CoAl alloy with a composition of 86.1 wt pct Co and 13.9 wt pct Al. The final product of the vaporized Li was in the form of Li(OH) due to the exposure to water vapor in the atmosphere upon collection. This aluminothermic approach is considered as a promising method to recover Li and Co from waste LiCoO2.

Ultra-thin and Mechanically Stable LiCoO2-Electrolyte Interphase Enabled by Mg2+ Involved Electrolyte.

LiCoO2 (LCO) cathode materials have attracted significant attention for its potential to provide higher energy density in current Lithium-ion batteries (LIBs). However, the structure and performance degradation are exacerbated by increasing voltage due to the catastrophic reaction between the applied electrolyte and delithiated LCO. The present study focuses on the construction of physically and chemically robust Mg-integrated cathode-electrolyte interface (MCEI) to address this issue, by incorporating Magnesium bis(trifluoromethanesulfonyl)imide (Mg[TFSI]2) as an electrolyte additive. During formation cycles, the strong MCEI is formed and maintained its 2nm thickness throughout long-term cycling. Notably, Mg is detected not only in the robust MCEI, but also imbedded in the surface of the LCO lattice. As a result, the parasitic interfacial side reactions, surface phase reconstruction, particle cracking, Co dissolution and shuttling are considerably suppressed, resulting in long-term cycling stability of LCO up to 4.5V. Therefore, benefit from the double protection of the strong MCEI, the Li||LCO coin cell and the Ah-level Graphite||LCO pouch cell exhibit high capacity retention by using Mg-electrolyte, which are 88.13% after 200 cycles and 90.4% after 300 cycles, respectively. This work provides a novel approach for the rational design of traditional electrolyte additives.

Understanding the role of TiO2 coating for stabilizing 4.6V high-voltage LiCoO2 cathode materials

TiO2 surface coating is considered to be an effective strategy for improving the cycling performance of commercially available high voltage LiCoO2 (HV-LCO) batteries. However, the mechanism underlying the TiO2 coating remains ambiguous due to the synergy of solid-state coating and annealing processes. In this work, the effects of TiO2 were systematically studied for 4.6 V HV-LCO batteries. The results showed that the coated TiO2 can be transformed into LiTiO2-rich layer, which can reduce surface residual lithium (SRL), lower the formation of Co3O4 and LiF-rich cathode electrolyte interphase (CEI) layer. Moreover, the annealed sample delivered improved surface texture, reduced specific surface area, and lower SRL, which was beneficial to improve the rate capability and cyclic performance. However, the LCO after annealing and coating exhibited weak static oxygen stability at high voltage due to the change in bulk Li/Co stoichiometry, leading to higher gas production. This work provides new insights into the effects of metal oxide coating and sheds light on the commercial process for HV-LCO.

Short-Process Regeneration of Highly Stable Spherical LiCoO2 Cathode Materials from Spent Lithium-Ion Batteries through Carbonate Precipitation.

High-efficacy recycling of spent lithium cobalt oxide (LiCoO2 ) batteries is one of the key tasks in realizing a global resource security strategy due to the rareness of lithium (Li) and cobalt (Co) resources. However, it is of great significance to develop the innovative recycle methods for spent LiCoO2 , simultaneously realizing the efficient recovery of valuable elements and the regeneration of high-performance LiCoO2 . Herein, a novel strategy of regenerating LiCoO2 cathode is proposed, which involves the preparation of micro-spherical aluminum (Al)-doped lithium-lacked precursor (Li2x Co1-x-y Al2/3y CO3, remarked as "PLCAC") via ammonium bicarbonate coprecipitation. The comprehensive conditions affecting particle growth kinetics, morphology and particle size the has been investigated in detail by physical characterizations and electrochemical measurements. And the optimized Al-doped LiCoO2 materials with high-density sphericity (LiCo1-z Alz O2 , remarked as "LCAO") shows a high initial specific capacity of 161 mAh g-1 at 0.1 C and excellent capacity retention of 99.5 % within 100 cycles at 1 C in the voltage range of 2.8 to 4.3 V. Our work provides valuable insights into the featured design of LiCoO2 precursors and cathode materials from spent LiCoO2 batteries, potentially guaranteeing the high-efficacy recycling and utilization of strategic resources.

Recovery of cobalt based materials from spent Li-ion batteries and their use as electrode material for supercapacitor

In this work, Co(OH)2 and Co3O4 were obtained to be used in coin cell-type supercapacitors from a lithium-ion battery whose cathode material is LiCoO2 for the first time in the literature. Firstly, LiCoO2 cathode material was taken from the dismantled li-ion battery, and leaching of cathode material was carried out using HNO3 and H2O2. Leaching was performed with a maximum yield of approximately 94 %. Then Co(OH)2 was precipitated in a basic medium by using a NaOH solution. Thermal analysis was applied to the produced Co(OH)2 to determine the behavior for conversion from Co(OH)2 to Co3O4. Two different Co3O4 powders were obtained as Co3O4-450 and Co3O4-1000 by calcination of precipitated Co(OH)2 at 450 and 1000 °C. Produced powders were characterized by lots of characterization methods such as XRD, Raman, SEM and BET. Three different electrode material for the coin cell type asymmetric supercapacitor cathode was made from produced powders by mixing with carbon black and PVDF. GCD, CV and EIS measurements were used evaluate the electrochemical properties of the supercapacitors. The maximum areal capacitance value of 98 mF.cm−2 was obtained at 10 mV/s scan rate in Co3O4-450 based supercapacitor.

Enhancing the Stability of 4.6 V LiCoO2 Cathode Material via Gradient Doping.

LiCoO2 (LCO) can deliver ultrahigh discharge capacities as a cathode material for Li-ion batteries when the charging voltage reaches 4.6 V. However, establishing a stable LCO cathode at a high cut-off voltage is a challenge in terms of bulk and surface structural transformation. O2 release, irreversible structural transformation, and interfacial side reactions cause LCO to experience severe capacity degradation and safety problems. To solve these issues, a strategy of gradient Ta doping is proposed to stabilize LCO against structural degradation. Additionally, Ta1-LCO that was tuned with 1.0 mol% Ta doping demonstrated outstanding cycling stability and rate performance. This effect was explained by the strong Ta-O bonds maintaining the lattice oxygen and the increased interlayer spacing enhancing Li+ conductivity. This work offers a practical method for high-energy Li-ion battery cathode material stabilization through the gradient doping of high-valence elements.

High-voltage stability and electrochemical performance of polyacrylic acid–xanthan gum copolymer-reinforced LiCoO2 cathode material

High-voltage LiCoO2 (LCO) cathode materials are in increasing demand in industry, but their stability is greatly affected by serious irreversible phase transitions and interfacial reactions at high voltages.

Unveiling Oxygen Evolution Reaction on LiCoO2 Cathode: Insights for the Development of High‐Performance Aqueous Lithium‐ion Batteries

AbstractAqueous lithium‐ion batteries (ALIBs) are attracting significant attention as promising candidates for safe and sustainable energy storage systems. This paper delves into the crucial aspects of ALIB technology focusing on the interaction between LiCoO2 (lithium cobalt oxide) cathode material and water electrolytes, with a specific emphasis on the Oxygen Evolution Reaction (OER) process. Fundamental understanding of the electrochemical behavior of LiCoO2 in aqueous electrolytes is crucial for enhancing the performance, safety, and longevity of ALIBs using LiCoO2 as the cathode material.Through a comprehensive periodic density functional analysis of the LiCoO2‐water at the cathode interface, the potential catalytic contributions to the OER mechanism of LiCoO2 are explored. The catalytic properties of LiCoO2 towards OER are investigated considering different steady states of the lowest energy surfaces of LiCoO2 and three different Li concentrations. Our results do not predict the formation of oxygen gas due to the expected large overpotentials, although the exergonic water decomposition to hydroxyl by means the first proton‐electron transfer is predicted at equilibrium potential. This work contributes to the fundamental understanding of LiCoO2 as cathode for aqueous lithium‐ion batteries, reporting the pros and cons of one of the most common cathode materials for traditional non‐aqueous batteries.