LiCoO2 Research Articles

Boosting High-Voltage Practical Lithium Metal Batteries with Tailored Additives

HighlightsFGN-182 electrolytes exhibit highly reversible Li plating/stripping with an average Coulombic efficiency reaching up to 99.56% determined from Auerbach’s test.The gas-evolution process of LiNO3 in high-voltage lithium cobalt oxide (LCO) cathodes is revealed by in situ differential electrochemical mass spectrometry.Pouch cells equipped with high-loading LCO (3 mAh cm−2) cathodes, ultrathin Li chips (25 μm), and lean electrolytes (5 g Ah−1) using optimized electrolyte (FGN-182 + 1%HTCN) demonstrate outstanding cycling performance.

Simultaneously achieving high Li leaching efficiency and Li/Co selectivity from lithium-ion batteries cathode by using natural low-melting mixture solvents (LoMMSs) as green solvents

Simultaneously achieving high Li leaching efficiency and Li/Co selectivity from lithium-ion batteries cathode at mild condition with high sustainability is difficult up to now. To achieve this goal, we here utilize amino acid-based low-melting mixture solvents (LoMMSs) as green solvents. Representative LoMMSs valine:lactic acid (1:12) could leach nearly 100% Li with the high Li/Co selectivity of 48.39 from lithium cobalt oxide (LCO). Effect of temperature, time and leaching agent mass is investigated. Higher temperature continuously increases the Li leaching efficiency, while Co leaching efficiency first increases during the temperature from 25 °C to 60 °C and then decreases at higher temperature. Both Li and Co leaching efficiency when extending the time or adding the leaching agent mass. Mechanism study shows that acid-base interaction and coordination are the main interaction for the high efficiency of metal leach while redox reaction is negligible. This work would provide a useful guide for promoting the industrial application of selectively recycling lithium-ion batteries cathode with high sustainability and low cost.

Enhancing Lithium-Sulfur Battery Performance with MXene: Specialized Structures and Innovative Designs.

Established in 1962, lithium-sulfur (Li-S) batteries boast a longer history than commonly utilized lithium-ion batteries counterparts such as LiCoO2 (LCO) and LiFePO4 (LFP) series, yet they have been slow to achieve commercialization. This delay, significantly impacting loading capacity and cycle life, stems from the long-criticized low conductivity of the cathode and its byproducts, alongside challenges related to the shuttle effect, and volume expansion. Strategies to improve the electrochemical performance of Li-S batteries involve improving the conductivity of the sulfur cathode, employing an adamantane framework as the sulfur host, and incorporating catalysts to promote the transformation of lithium polysulfides (LiPSs). 2D MXene and its derived materials can achieve almost all of the above functions due to their numerous active sites, external groups, and ease of synthesis and modification. This review comprehensively summarizes the functionalization advantages of MXene-based materials in Li-S batteries, including high-speed ionic conduction, structural diversity, shuttle effect inhibition, dendrite suppression, and catalytic activity from fundamental principles to practical applications. The classification of usage methods is also discussed. Finally, leveraging the research progress of MXene, the potential and prospects for its novel application in the Li-S field are proposed.

Integrating chemistry knowledge in large language models via prompt engineering

This paper presents a study on the integration of domain-specific knowledge in prompt engineering to enhance the performance of large language models (LLMs) in scientific domains. The proposed domain-knowledge embedded prompt engineering method outperforms traditional prompt engineering strategies on various metrics, including capability, accuracy, F1 score, and hallucination drop. The effectiveness of the method is demonstrated through case studies on complex materials including the MacMillan catalyst, paclitaxel, and lithium cobalt oxide. The results suggest that domain-knowledge prompts can guide LLMs to generate more accurate and relevant responses, highlighting the potential of LLMs as powerful tools for scientific discovery and innovation when equipped with domain-specific prompts. The study also discusses limitations and future directions for domain-specific prompt engineering development.

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.

Controllable synthesis of carbon supported cobalt monoxide anode and high-voltage lithium cobalt oxide cathode with enhanced lithium-ion storage

Natural macromolecule amylose (AM) is employed to deoxygenate few-layered graphene oxide (GO) and modulate the surface interaction between GO sheets and Co2+ ions under mild hydrothermal conditions. The obtained Co2+ ions and AM molecule jointly decorated reduced graphene oxide (Co-AM/RGO) sample is further utilized to synthesize both anode and cathode materials with controlled microstructures. To synthesize anode material, the Co-AM/RGO can be directly converted to a hierarchical AM pyrolyzed carbon and RGO supported cobalt monoxide nanocomposite (CoO@AMC/RGO) after a simple inert gas protected thermal treatment. To synthesize cathode material, a carbon coated nano-sized lithium cobalt oxide sample (LiCoO2/C, LCO/C) can be obtained after a solid-state reaction in air by mixing lithium salt with the Co-AM/RGO. The CoO and LCO nanocrystals with significantly controlled sizes are well dispersed in the carbon matrices. The CoO@AMC/RGO anode shows a high reversible capacity of 785.25 mAh·g−1 after 500 cycles at 200 mA·g−1 and 608.25 mAh·g−1 after 700 cycles at 1000 mA·g−1, while the LCO/C cathode delivers a superior reversible capacity of 140.91 mAh·g−1 after 1000 cycles at 1000 mA·g−1 with a high cut-off voltage of 4.6 V. This work provides a new perspective for controllable engineering of electrode materials with enhanced lithium-ion storage performances.

Synthesis of LiCo1-XNiXO2 nanomaterial by hydrothermal method as cathode for lithium ion battery

The compounds of LiCoO2 (LCO) and LiCo1-xNixO2 (LCNO), with (x=0,0.25,0.5,0.75,1) were synthesized as cathode active material for lithium–ion batteries using hydrothermal technique in this study. Structure and morphology characterization were conducted for all prepared samples. The crystalline results indicate that both LCO and LCNO possess a rhombohedral structure, while the morphology results show irregular shapes. Electrochemical tests were carried out for LiCoO2 and LiCo0.25 Ni0.75O2 samples only. From the electrochemical measurements, the LiCo0.25 Ni0.75O2 demonstrate higher charge and discharge capacities compared to the LiCoO2 electrode, findings which are consistent with the electrochemical impedance spectroscopy (EIS) results. The X-ray diffraction (XRD) results of both the prepared Lithium Cobalt Oxide (LCO) and Lithium Cobalt Nickel Oxide (LCNO) samples reveal characteristic peaks at specific angles (2θ) indicating crystallographic planes. For LCO, peaks were observed at 18.96°, 37.40°, 38.35°, 39.07°, 45.29°, 49.45°, and 59.62° corresponding to crystallographic planes (003), (101), (006), (012), (104), (015), and (107) respectively. These peaks confirm the formation of a rhombohedral LiCoO2 nanostructure with space group (R-3m no.166), consistent with standard data (JCPDS 00-016-0427). The EDX spectra of the synthesized Lithium Cobalt Oxide (LCO) and Lithium Cobalt Nickel Oxide (LCNO) were analyzed. The results showed the presence of oxygen (O), cobalt (Co), and nickel (Ni) elements. However, the peak corresponding to lithium (Li) was not visible due to its low activation energy. Finally, the synthesis and characterization of LiCoO2 (LCO) and LiCo1-xNixO2 (LCNO) compounds were conducted, with electrochemical tests indicating superior performance of LiCo0.25 Ni0.75O2 over LiCoO2

Recovery of lithium and cobalt from lithium cobalt oxide and lithium nickel manganese cobalt oxide batteries using supercritical water

This study investigates the eco-friendly extraction of metal oxides from LCO and NMC batteries using supercritical water. Experiments were conducted at 450 °C with a feed rate of 5 mL min−1 and varying battery/PVC ratios (0.0, 2.0, and 3.0). The products were analyzed by X-ray diffractometry (XRD), atomic absorption spectrometry (FAAS) and gas chromatography-mass spectrometry (GC-MS). Results show the presence of cobalt chloride (CoCl2) and lithium (Li) in the liquid products, achieving 100% cobalt recovery under all conditions. The gaseous products obtained hydrogen with molar compositions up to 78.3% and 82.7% for LCO:PVC and NMC:PVC batteries, respectively, after 60 min of reaction. These findings highlight the potential of this methodology for lithium-ion battery recycling.

A Formula to Customize Cathode Binder for Lithium Ion Battery

AbstractThe binder plays a crucial role in binding the solid electrode components and fixing them to the current collector, ensuring good contact and transformation. The high‐energy‐density cathode poses several challenges for the Polyvinylidene fluoride (PVDF) binder, such as high electrode potential, mass loading, and binding force. Although various new binders are proposed to optimize the electrochemical performance of cathode, the design focus and mechanisms often lack universality. This study introduces a design strategy for the cathode binder from the perspective of molecular structure design. The performance of the binder is optimized by adjusting the soft‐hard and hydrophilic‐hydrophobic balances of the polymer, and the effectiveness of this strategy is verified in the LiCoO2 (LCO) system. The optimized copolymer binder improves the cycling stability of the LCO electrode under high load and low binder content conditions and even achieves stable operation at a high charging voltage of 4.6 V. The mechanism for improving the performance of LCO electrodes is that the optimized binder stabilizes the electrode structure, the active material particle structure, and the active material interface. This design strategy provides a valuable reference for customizing cathode binders.

Solid-State Electrocatalysis in Heteroatom-Doped Alloy Anode Enables Ultrafast Charge Lithium-Ion Batteries.

Electrocatalysis is generally confined to dynamic liquid-solid and gas-solid interfaces and is rarely applicable in solid-state reactions. Here, we report a paradigm shift strategy to exploit electrocatalysis to accelerate solid-state reactions in the context of lithium-ion batteries (LIBs). We employ heteroatom doping, specifically boron for silicon and sulfur for phosphorus, to catalyze electrochemical Li-alloying reactions in solid-state electrode materials. The preferential cleavage of polar dopant-host chemical bonds upon lithiation triggers chemical bond breaking of the host material. This solid-state catalysis, distinct from liquid and gas phases, requires a critical doping concentration for optimal performance. Beyond a critical concentration of ∼1 atom %, boron and sulfur doping drastically reduces activation energies and accelerates redox kinetics during lithiation/delithiation processes, leading to markedly enhanced rate performance in boron-doped silicon and sulfur-doped black/red phosphorus anode. Notably, a sulfur-doped black phosphorus anode coupled with a lithium cobalt oxide cathode achieves an ultrafast-charging battery, recharging 80% energy of a battery in 302 Wh kg-1 in 9 min, surpassing the thus far reported LIBs.

Fucoidan Cross‐Linking Polyacrylamide as Multifunctional Aqueous Binder Stabilizes LiCoO2 to 4.6 V

AbstractRaising the cutoff voltage can efficiently increase the energy density of lithium cobalt oxide (LCO). However, upon charging over 4.55 V the LCO undergoes irreversible phase transition from the pristine O3 phase to the metastable H1‐3 phases, causing serious side reactions, which results in poor cycling stability. Herein, a multifunctional aqueous composite binder derived from the cross‐linking of fucoidan (FUC) and polyacrylamide (PAM) is developed to enhance the stability of LCO cathode at 4.6 V. The cross‐linking interaction of FUC and PAM provides a uniform coating on the surface of LCO and ensures a high peel strength for the electrode, effectively mitigating irreversible phase transition and detrimental interface side reactions. More importantly, the sulfur ester and amide groups of FUC‐PAM favorably function as surface charge compensators to the high valent Co upon charging under high voltages, thus stabilizes the surface lattice of LCO and suppresses the detrimental oxygen release. As expected, the LCO with a cutoff voltage of 4.6 V exhibits a high capacity retention of 90% after 100 cycles at a current density of 110 mA g−1. The interfacial coordination effect of composite binders offers a novel strategy to enhance the stability of high‐voltage LCO for high‐energy lithium‐ion batteries.

A solid-state surface-to-bulk modification with a multifunctional modified layer for 4.6 V LiCoO2

With the attempts of more than 30 years, the current commercial LiCoO2 (LCO) offers a reversible capacity of 185 mAh g−1 with a cut-off voltage of 4.5 V vs. Li+/Li. Further increasing the cut-off voltage, more lithium-ions can extract, deeply enhancing the capacity and energy density. However, it results in numerous side reactions and a significant decay in battery cycle performance. To address these issues, Nano-LiNbO3 as a coating agency is introduced by a solid-state surface-to-bulk modification process. To avoid the agglomeration and achieve uneven coating of Nano-LiNbO3 in the solid-state reaction, polyvinylpyrrolidone (PVP) is introduced as a dispersant, which effectively ensures the uniform and smooth coating along with the carbonization process. The modified LCO sample presents a specific reversible capacity of 215.5 mAh g−1 in the initial cycle and a capacity retention rate of 90 % after 100 cycles at 3–4.6 V and 0.5 C. Further analysis demonstrate that the LiNbO3 surface coating layer and the element gradient doping layer provide LCO a stable structure and an inert surface, which improves the surface stability, suppresses the oxygen release and ensures the enhanced electrochemical performance.

Controlling lithium cobalt oxide phase transition using molten fluoride salt for improved lithium-ion batteries

LiCoO2 is a historic lithium-ion battery cathode that continues to be used today because of its high energy density. However, the practical capacity of LiCoO2 is limited owing to the harmful phase transition at high voltages, which prevents the realization of its theoretical capacity. Here, we treat LiCoO2 particles with a molten salt of MgF2–LiF as a reaction accelerator to facilitate the diffusion and doping of magnesium into bulk LiCoO2 and to form a stable coating layer on the particle surface. Ex situ X-ray diffraction analysis confirms the inhibition of the harmful phase transition and the emergence of a different phase as the modified LiCoO2 was charged up to 4.7 V. The modified LiCoO2 shows high electrochemical performance during high-voltage operation. This technology provides a guideline for the suppressing fundamental degradation associated with phase transition and achieving ultra-high energy density LiCoO2 cathodes.

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.

Ultrathin Titanium Dioxide Coating Enables High-Rate and Long-Life Lithium Cobalt Oxide.

Lithium cobalt oxide (LCO) has been widely used as a leading cathode material for lithium-ion batteries in consumer electronics. However, unstable cathode electrolyte interphase (CEI) and undesired phase transitions during fast Li+ diffusivity always incur an inferior stability of the high-voltage LCO (HV-LCO). Here, an ultra-thin amorphous titanium dioxide (TiO2) coating layer engineered on LCO by an atomic layer deposition (ALD) strategy is demonstrated to improve the high-rate and long-cycling properties of the HV-LCO cathode. Benefitting from the uniform TiO2 protective layer, the Li+ storage properties of the modified LCO obtained after 50 ALD cycles (LCO-ALD50) are significantly improved. The results show that the average Li+ diffusion coefficient is nearly tripled with a high-rate capability of 125 mAh g-1 at 5C. An improved cycling stability with a high-capacity retention (86.7%) after 300 cycles at 1C is also achieved, far outperforming the bare LCO (37.9%). The in situ XRD and ex situ XPS results demonstrate that the dense and stable CEI induced by the surface TiO2 coating layer buffers heterogenous lithium flux insertion during cycling and prevents electrolyte, which contributes to the excellent cycling stability of LCO-ALD50. This work reveals the mechanism of surface protection by transition metal oxides coating and facilitates the development of long-life HV-LCO electrodes.

Scalable Precise Nanofilm Coating and Gradient Al Doping Enable Stable Battery Cycling of LiCoO2 at 4.7 V

AbstractThe quest for smart electronics with higher energy densities has intensified the development of high‐voltage LiCoO2 (LCO). Despite their potential, LCO materials operating at 4.7 V faces critical challenges, including interface degradation and structural collapse. Herein, we propose a collective surface architecture through precise nanofilm coating and doping that combines an ultra‐thin LiAlO2 coating layer and gradient doping of Al. This architecture not only mitigates side reactions, but also improves the Li+ migration kinetics on the LCO surface. Meanwhile, gradient doping of Al inhibited the severe lattice distortion caused by the irreversible phase transition of O3−H1−3−O1, thereby enhanced the electrochemical stability of LCO during 4.7 V cycling. DFT calculations further revealed that our approach significantly boosts the electronic conductivity. As a result, the modified LCO exhibited an outstanding reversible capacity of 230 mAh g−1 at 4.7 V, which is approximately 28 % higher than the conventional capacity at 4.5 V. To demonstrate their practical application, our cathode structure shows improved stability in full pouch cell configuration under high operating voltage. LCO exhibited an excellent cycling stability, retaining 82.33 % after 1000 cycles at 4.5 V. This multifunctional surface modification strategy offers a viable pathway for the practical application of LCO materials, setting a new standard for the development of high‐energy‐density and long‐lasting electrode materials.

Scalable Precise Nanofilm Coating and Gradient Al Doping Enable Stable Battery Cycling of LiCoO2 at 4.7 V.

The quest for smart electronics with higher energy densities has intensified the development of high-voltage LiCoO2 (LCO). Despite their potential, LCO materials operating at 4.7 V faces critical challenges, including interface degradation and structural collapse. Herein, we propose a collective surface architecture through precise nanofilm coating and doping that combines an ultra-thin LiAlO2 coating layer and gradient doping of Al. This architecture not only mitigates side reactions, but also improves the Li+ migration kinetics on the LCO surface. Meanwhile, gradient doping of Al inhibited the severe lattice distortion caused by the irreversible phase transition of O3-H1-3-O1, thereby enhanced the electrochemical stability of LCO during 4.7 V cycling. DFT calculations further revealed that our approach significantly boosts the electronic conductivity. As a result, the modified LCO exhibited an outstanding reversible capacity of 230 mAh g-1 at 4.7 V, which is approximately 28 % higher than the conventional capacity at 4.5 V. To demonstrate their practical application, our cathode structure shows improved stability in full pouch cell configuration under high operating voltage. LCO exhibited an excellent cycling stability, retaining 82.33 % after 1000 cycles at 4.5 V. This multifunctional surface modification strategy offers a viable pathway for the practical application of LCO materials, setting a new standard for the development of high-energy-density and long-lasting electrode materials.

Enhancing electrochemical capacity and interfacial stability of lithium-ion batteries through side reaction modulation with ultrathin carbon nanotube film and optimized lithium cobalt oxide particle size

Enhancing electrochemical capacity and interfacial stability of lithium-ion batteries through side reaction modulation with ultrathin carbon nanotube film and optimized lithium cobalt oxide particle size

Exploring Phenolphthalein Polyarylethers as High-Performance Alternative Binders for High-Voltage Cathodes in Lithium-Ion Batteries.

Polyvinylidene fluoride (PVDF) has unique electrochemical oxidation resistance and is the only binder for high-voltage cathode materials in the battery industry for a long time. However, PVDF still has some drawbacks, such as environmental limitations on fluorine, strict requirements for environmental humidity, weak adhesion, and poor lithium ion conductivity. Herein, the long-standing issues associated with high-voltage lithium cobalt oxide (LiCoO2; LCO) are successfully addressed by incorporating phenolphthalein polyetherketone (PEK-C) and phenolphthalein polyethersulfone (PES-C) as binder materials. These binders have unexpected electrochemical oxidation resistance and robustness adhesion, ensure uniform coverage on the surface of LCO, and establish an effective and fast ion-conductive CEI/binder composite layer. By leveraging these favorable characteristics, electrodes based on polyarylether binders demonstrate significantly better cycling and rate performance than their counterparts using traditional PVDF binders. The fast ion-conductive CEI/binder composite layer effectively mitigates adverse reactions at the cathode-electrolyte interface. As anticipated, batteries utilizing phenolphthalein polyarylether binders exhibit capacity retention rates of 88.92% and 80.4% after 200 and 500 cycles at 4.5 and 4.6V, respectively. The application of binders, such as polyarylether binders, offers a straightforward and inspiring approach for designing high-energy-density battery materials.

Rapid Release of Silicon by Ultrafast Joule Heating Generates Mechanically Stable Shell-Shell Si/C Anodes with Dominant Inward Deformation.

As a promising anode material, silicon-carbon composites encounter great challenges related to internal stress release and contact between the composites during lithiation. These issues lead to material degradation and concomitantly rapid capacity decline. Here, we report a type of shell-shell silicon-carbon (SS-Si/C) composite, which consists of a carbon shell tightly coated with a silicon shell. The mechanical analysis unveils that the dominant inward expansion of the Si shell is achieved through the synergistic effect of the outer carbon shell and the inner hollow structure. Benefiting from the well-tailored shell-shell structure, the SS-Si/C anode exhibits exceptional performance, boasting a high specific capacity (1690.3 mA h g-1 after 550 cycles at 0.5 A g-1), a high areal capacity (2.05 mA h cm-2 after more than 400 cycles at 0.5 mA cm-2), and an extended cycling life (1055.6 mA h g-1 after 1000 cycles at 8 A g-1), far exceeding commercially available Si/C anodes. Using the well-designed SS-Si/C anode, full cells assembled with LiCoO2 (LCO) or LiFePO4 (LFP) cathodes achieve favorable rate capability and cyclic stability. Notably, at a high rate of 6 C (1 C = 170 and 270 mA g-1 for LFP and LCO, respectively), these full cells deliver high specific capacities of 79.5 mA h g-1 and 64.9 mA h g-1 when using LCO and LFP, respectively, demonstrating the potential of SS-Si/C anodes for practical applications. The straightforward and safe synthesis method in this work enables the rational design of hollow structures with distinct properties.