LiCoO2 Research Articles

Directly Regenerating of Spent LiCoO2 with Gradient F-Doped Subsurface towards Ultra-Stable Storage Properties.

As great potential recycling strategy, the direct regeneration of spent LiCoO2 (LCO) is beneficial for lowering environmental pollutions and promoting global sustainability. However, owing to the using of binder and electrolyte, some fluorine impurities would be remained into spent materials. Considering the doping behaviors of F-elements, their suitable content introducing would facilitate the energy-storage abilities of regenerated LCO. Herein, through the tailored introduction of F-elements, spent LCO are successfully regenerated with physical-chemical evolutions. Benefitting from the existed oxygen vacancies, the diffusion energy-barrier of F-elements is reduced from 1.73 eV to 0.61 eV, facilitating the establishment of gradient F-doped subsurface, along with the formation of rigid CoO5F. Meanwhile, excess F-elements (1 wt %, as a threshold) lead to the formation of LiF passivation layer on the surface. Thus, the as-optimized sample displays a considerable capacity of 154.4 mAh g-1 even at 5.0 C, with retention rate (88.3 %) in 3.0-4.5 V. Supported by detailed electrochemical and kinetic analysis, the structural advantages are confirmed to boost the improved redox activity of Co-ions and the alleviating of irreversible oxygen-release. Give this, the work is anticipated to reveal the evolutions of regenerated LCO with the introduced F-elements, whilst providing the practical regeneration strategies toward excellent high-voltage properties.

Directly Regenerating of Spent LiCoO2 with Gradient F‐Doped Subsurface towards Ultra‐Stable Storage Properties

AbstractAs great potential recycling strategy, the direct regeneration of spent LiCoO2 (LCO) is beneficial for lowering environmental pollutions and promoting global sustainability. However, owing to the using of binder and electrolyte, some fluorine impurities would be remained into spent materials. Considering the doping behaviors of F‐elements, their suitable content introducing would facilitate the energy‐storage abilities of regenerated LCO. Herein, through the tailored introduction of F‐elements, spent LCO are successfully regenerated with physical‐chemical evolutions. Benefitting from the existed oxygen vacancies, the diffusion energy‐barrier of F‐elements is reduced from 1.73 eV to 0.61 eV, facilitating the establishment of gradient F‐doped subsurface, along with the formation of rigid CoO5F. Meanwhile, excess F‐elements (1 wt %, as a threshold) lead to the formation of LiF passivation layer on the surface. Thus, the as‐optimized sample displays a considerable capacity of 154.4 mAh g−1 even at 5.0 C, with retention rate (88.3 %) in 3.0–4.5 V. Supported by detailed electrochemical and kinetic analysis, the structural advantages are confirmed to boost the improved redox activity of Co‐ions and the alleviating of irreversible oxygen‐release. Give this, the work is anticipated to reveal the evolutions of regenerated LCO with the introduced F‐elements, whilst providing the practical regeneration strategies toward excellent high‐voltage properties.

Surface Engineering via Rare Earth Oxide Composite Coating to Enhance the High-Voltage Stability of the LiCoO2 Cathode.

The commercial application of high-voltage LiCoO2 (LCO) faces significant challenges due to rapid capacity decay, primarily attributed to an unstable interface and structure at deeply delithiated states. Herein, a unique rare earth oxide composite coating comprising La2O3, Y2O3, and LaYO3 has been prepared to stabilize LCO at high voltage. The synergistic effect between these rare earth oxides significantly reinforces the protective capabilities of the coating, effectively enhancing the interfacial/structural stability of LCO. When tested at 4.6 V, the coated LCO exhibits an excellent capacity retention of 94.4% after 300 cycles at 1 C. Even after an ultralong charge/discharge test of 700 cycles at 2 C, the coated LCO retains 85.2% of its initial specific capacity, which significantly outperforms the uncoated LCO (6.3%). Moreover, the coated LCO shows enhanced cycling performance at a high temperature of 45 °C, owing to the outstanding thermal stability of the La-Y-O composite. Additionally, the superior cycling stability of the coated LCO at 4.7 V, compared to the uncoated LCO, demonstrated the promising potential of the La-Y-O composite coating in improving electrochemical performance of LCO at higher cutoff voltages. These findings highlight an efficacious strategy to enhance the interfacial/structural stability of high-voltage LCO using rare earth oxides.

In Situ Constructing Robust Interface by Deep Eutectic Polymeric Electrolyte Enables High Performance Lithium Metal Batteries with High-Loading Cathode.

The low Li+ transport and poor interface have consistently been two major impediments to practical applications of Polyacrylonitrile (PAN)-based composite solid-state electrolytes (PCPE). In this work, a polymerizable deep eutectic electrolyte is meticulously designed with high fluidity which consists of Poly (Ethylene Glycol) Diacrylate (PEGDA), Fluoroethylene Carbonate (FEC), Succinonitrile (SN) and dual salts (LiTFSI/LiDFOB) to promote Li+ transport and ameliorate the interface of PCPE. Inclusion of PEGDA monomers and FEC alters the crystallinity of SN, enhancing the wettability of thick electrode, and formation of polymeric 3D network from polymerization of PEGDA can anchor SN and suppress the side reactions between SN and lithium metal. Consequently, the modified PCPE exhibit an enhanced conductivity of 4.47×10-4Scm-1 with Li-ion transference number of 0.60, and show an excellent lithium stability. LiCoO2(LCO)/SP-PCPE/Li batteries with higher loading (3-4.4V, 6mgcm-2) can work for over 300 cycles at 0.5 C. Even with an ultra-high loading of 16mgcm-2, LCO/SP-PCPE/Li batteries achieve an excellent cycling performance. This work provides new insights into how to construct a robust interface for solid-state batteries with high-loading cathode.

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.

High-fidelity reconstruction of porous cathode microstructures from FIB-SEM data with deep learning

Accurate modeling of lithium-ion battery (LIB) electrode microstructures provides essential references for understanding degradation mechanisms and optimizing materials. Traditional segmentation methods often struggle to accurately capture the complex microstructures of porous LIB electrodes in focused ion beam scanning electron microscopy (FIB-SEM) data. In this work, we develop a deep learning model based on the Swin Transformer to segment FIB-SEM data of a lithium cobalt oxide electrode, utilizing fused secondary and backscattered electron images. The proposed approach outperforms other deep learning methods, enabling the acquirement of 3D microstructure with reduced particle elongated artifacts. Analyses of the segmented microstructures reveal improved electrode tortuosity and pore connectivity crucial for ion and electron transport, emphasizing the necessity of accurate 3D modeling for reliable battery performance predictions. These results suggest a path toward voxel-level degradation analysis through more sensible battery simulation on high-fidelity microstructure models directly twinned from real porous electrodes.

Regulating solvated sheath with anion chelant enables 4.6 V ultra-stable commercial LiCoO2.

Increasing cut-off voltage of lithium cobalt oxide (LCO) (> 4.6 V) is an effective strategy to satisfy the ever-increasing demand for high energy density. However, the irreversible phase transition significantly destroys the structure of high-voltage LCO, especially the surface lattice. Considering that the structural stability of LCO is primarily dominated by the intrinsic merits of electrode-electrolyte interface (EEI), we explored and disclosed the operating mechanism of anion chelating agent tris(pentafluorophenyl) borane (TPFPB) and regulate the CEI layer on LCO electrode. Benefiting from the high HOMO energy level and preferential decomposition of TPFPB-PF6-, a robust LiF-rich CEI layer is constructed and greatly improves the stability of electrode/electrolyte interface. The well-designed electrolyte composed of 1 mol L-1 LiPF6 in EC/EMC with TPFPB additives endows Li/LCO half cells and 4 Ah Gr/LCO pouch cell with enhanced cycling stability under a high voltage condition. This work provides pave a new direction for the development of economical high-voltage LIBs.

A Universal Plug-and-Play Approach to In Situ Multinuclear Magnetic Resonance Analysis of Electrochemical Phenomena in Commercial Battery Cells.

Advancing electrochemical energy storage devices relies on versatile analytical tools capable of revealing the molecular mechanisms behind the function and degradation of battery materials in situ. The nuclear magnetic resonance phenomenon plays a pivotal role in fundamental studies of energy materials and devices because of its exceptional sensitivity to local environments and the dynamics of many electrochemically relevant elements. The jelly roll architecture is one of the most energy-dense and, therefore, most popular concepts implemented in pouch, prismatic, and cylindrical Li- and Na-ion cells. Such widely commercialized designs, however, represent a significant obstacle for a range of powerful in situ magnetic resonance-based methodologies due to negligible radio frequency electromagnetic field penetration through conductive metal casings and current collectors. In this work, we introduce an experimental setup that enables direct RF wave transmission through the cell terminals and current collectors, and provides efficient excitation and detection of NMR signals. An RF adapter designed as a plug-and-play device effectively turns the battery cell into an NMR probe that can be tuned to a broad range of Larmor frequencies. Due to its exceptional sensitivity, versatility, and multinuclear capability, the proposed methodology is suitable for fundamental research and industrial high-throughput screening applications. In situ NMR lineshapes provide a direct quantitative description of the chemical environments of electrochemically active elements and enable new metrics for the accurate assessment of state-of-charge (SoC) and state-of-health (SoH). Specifically, in commercial pouch cells based on lithium cobalt oxide, lithium nickel manganese cobalt oxide, and sodium nickel iron manganese oxide chemistries, 7Li and 23Na NMR data unambiguously show electrochemical transformations between intercalated and metallic forms of charge carrier ions, and reveal anisotropic magnetic properties of the electrode coating.

Characterization of Lithium-Ion Battery Fire Emissions—Part 2: Particle Size Distributions and Emission Factors

The lithium-ion battery (LIB) thermal runaway (TR) emits a wide size range of particles with diverse chemical compositions. When inhaled, these particles can cause serious adverse health effects. This study measured the size distributions of particles with diameters less than 10 µm released throughout the TR-driven combustion of cylindrical lithium iron phosphate (LFP) and pouch-style lithium cobalt oxide (LCO) LIB cells. The chemical composition of fine particles (PM2.5) and some acidic gases were also characterized from filter samples. The emission factors of particle number and mass as well as chemical components were calculated. Particle number concentrations were dominated by those smaller than 500 nm with geometric number mean diameters below 130 nm. Mass concentrations were also dominated by smaller particles, with PM1 particles making up 81–95% of the measured PM10 mass. A significant amount of organic and elemental carbon, phosphate, and fluoride was released as PM2.5 constituents. The emission factor of gaseous hydrogen fluoride was 10–81 mg/Wh, posing the most immediate danger to human health. The tested LFP cells had higher emission factors of particles and HF than the LCO cells.

Efficiency of Penicillium sp. and Aspergillus sp. for bioleaching lithium cobalt oxide from battery wastes in potato dextrose broth and sucrose medium

Lithium-ion batteries, a primary power source, generate electronic hazardous waste at the end of their lifespan, which is a richer source of highly concentrated metals such as cobalt and lithium than those in natural resources. The waste is a potential renewable resource for the extraction of metals. Bioleaching, a process utilizing microbial activity, was used in this study to investigate the cobalt and lithium leaching efficiency from battery wastes. Two fungal strains, Aspergillus sp. strain JMET 15 and Penicillium sp. strain JMET 24 were used with different organic carbon sources (sucrose medium and potato dextrose broth) at 1 % pulp density. The sucrose medium derived a higher acid quantity and leached higher concentration of cobalt and lithium than in potato dextrose broth. Leaching efficiency by JMET 24 was higher than JMET 15. Cobalt (32.57 % and 27.19 %) and lithium (65.07 % and 40.58 %) were bioleached by JMET 24 and JMET 15, respectively, after 30 d cultivation in the sucrose medium. Lower pulp density was conducted to achieved higher leaching efficiency by JMET24, cobalt (77.87 % and 74.5 %) and lithium (99.88 % and 78.4 %) were bioleached at 0.1 % and 0.5 % pulp density, respectively. Cobalt oxide (Co3O4) was the product of the one-step recovery (leaching and precipitation) process. Cobalt was transformed from lithium cobalt oxide to cobalt phosphate-oxalate by JMET 24 in the sucrose medium. Thus, the potential of bioleaching as an effective method for recovering valuable metals from lithium-ion battery waste is demonstrated, presenting a promising approach for both waste management and resource recovery.

Inhibiting the current spikes within the channel layer of LiCoO2-based three-terminal synaptic transistors

Synaptic transistors, which emulate the behavior of biological synapses, play a vital role in information processing and storage in neuromorphic systems. However, the occurrence of excessive current spikes during the updating of synaptic weight poses challenges to the stability, accuracy, and power consumption of synaptic transistors. In this work, we experimentally investigate the main factors for the generation of current spikes in the three-terminal synaptic transistors that use LiCoO2 (LCO), a mixed ionic-electronic conductor, as the channel layer. Kelvin probe force microscopy and impedance testing results reveal that ion migration and adsorption at the drain–source-channel interface cause the current spikes that compromise the device's performance. By controlling the crystal orientation of the LCO channel layer to impede the in-plane migration of lithium ions, we show that the LCO channel layer with the (104) preferred orientation can effectively suppress both the peak current and power consumption in the synaptic transistors. Our study provides a unique insight into controlling the crystallographic orientation for the design of high-speed, high-robustness, and low-power consumption nano-memristor devices.

Study on Cycle Performance and Rate Performance of Lithium Cobalt Oxide

Lithium cobalt oxide (LiCoO2 ) cathode material, with its high energy density and operating voltage, is currently a mainstream material for lithium-ion battery cathodes.   However,  the  crystal  structure  collapse  and  lattice  oxygen  evolution under high-voltage conditions lead to rapid capacity decay, severely limiting its practical applications.   This paper  analyzes the main factors affecting the cycle performance and rate performance of lithium cobalt oxide, considering the physic- ochemical properties of the particles, including elemental content and particle size, and provides a mathematical model linking these properties to electrochemical per- formance.  The study offers insights for the practical production of high-voltage lithium cobalt oxide materials. At the beginning, we embarked on investigating the correlation between the physicochemical attributes (encompassing elemental composition and particle size) of lithium cobalt oxide and its cycle performance. An Ordinary Least Squares (OLS) linear regression model was formulated, yielding a robust fit with an R-Squared value of 0.94. This model was subsequently optimized through the application of an XGBoost algorithm, achieving an R-Squared value nearing unity, signifying a remarkable enhancement in model accuracy. Visual analysis of the results pinpointed the primary determinants of cycle performance, arranged in descending order of significance: 'Cycle Index,' Mg content, particle size distribution (D10), Zn, and Al. Then, our attention shifted to examining the link between the aforementioned physicochemical characteristics and the rate performance of lithium cobalt oxide. The Jarque-Bera and Shapiro-Wilk tests confirmed the normality of the data, fulfilling the prerequisites for hypothesis testing. An OLS linear regression model was developed, demonstrating a strong goodness-of-fit with an R-Squared value exceeding 0.8. This model was further honed with an XGBoost model, which achieved an R-Squared score approaching 1, indicating a substantial refinement in model precision. The visualization of model outcomes illuminated the key factors influencing rate performance, ranked in descending order of importance: particle size distribution (D50), Al, Mn, Zn, Mg, Ni, and Fe. Lastly, we devised an optimal strategy that encompasses the incorporation of strategic doping elements, the utilization of high-temperature sol-gel methods to bolster cycle performance, and coating modifications aimed at enhancing rate performance. This holistic approach fosters the structural stability of lithium cobalt oxide crystals, fortifying their high-potential cycle capabilities, and concurrently elevating their rate performance.

Densification of Cathode/Electrolyte Interphase to Enhance Reversibility of LiCoO2 at 4.65V.

For LiCoO2 (LCO) operated beyond 4.55V (vs Li/Li+), it usually suffers from severe surface degradation. Constructing a robust cathode/electrolyte interphase (CEI) is effective to alleviate the above issues, however, the correlated mechanisms still remain vague. Herein, a progressively reinforced CEI is realized via constructing Zr─O deposits (ZrO2 and Li2ZrO3) on LCO surface (i.e., Z-LCO). Upon cycle, these Zr─O deposits can promote the decomposition of LiPF6, and progressively convert to the highly dispersed Zr─O─F species. In particular, the chemical reaction between LiF and Zr─O─F species further leads to the densification of CEI, which greatly reinforces its toughness and conductivity. Combining the robust CEI and thin surface rock-salt layer of Z-LCO, several benefits are achieved, including stabilizing the surface lattice oxygen, facilitating the interface Li+ transport kinetics, and enhancing the reversibility of O3/H1-3 phase transition, etc. As a result, the Z-LCO||Li cells exhibit a high capacity retention of 84.2% after 1000 cycles in 3-4.65V, 80.9% after 1500 cycles in 3-4.6V, and a high rate capacity of 160mAhg-1 at 16 C (1 C=200mAg-1). This work provides a new insight for developing advanced LCO cathodes.

Chemo-Mechanical Instabilities in Lithium Cobalt Oxide at Higher State-of-Charge in Li-Ion Batteries

Chemo-Mechanical Instabilities in Lithium Cobalt Oxide at Higher State-of-Charge in Li-Ion Batteries

Recycling spent battery components into highly efficient hydrogen and oxygen evolution electro-nano-catalysts

Inspired by the 'waste-to-resource' strategic theme for environmental recovery, here we present the recycling of spent dry cells and spent Lithium-ion batteries aiming to achieve the preparation of cheap and efficient electrocatalysts for Proton Exchange membrane electrolyzers instead of the precious-based electrocatalysts. Graphite doped with manganese (IV) oxide nanoparticles, graphite doped with manganese (IV) oxide and aluminum oxide nanoparticles, lithium cobalt oxide doped with copper oxide nanoparticles, and lithium cobalt oxide doped with copper oxide and zinc oxide nanoparticles synthesis procedures are done via hydrothermal method at a pressure of 4.5 Mpa at 180 ○C. Electrochemical characterization is done to determine overpotential, tafel slope, and electrocatalytic stability via a three-electrode system. The optimum results are observed by the graphite doped with manganese (IV) oxide nanoparticles, which show -55.06 mV and -41.33 mV/dec as overpotential and tafel slope at -10 mA/cm2 for hydrogen evolution reaction with surface area of 40.87 m2/g and 21.05 nm as crystal size and Graphite doped with manganese oxide and aluminum oxide nanoparticles, which show 321.58 mV and 174.14 mV/dec as overpotential and Tafel slope for oxygen evolution reaction at 10 mA/cm2 with surface area of 7.64 m2/g and 44.43 nm as crystal size.

Promoting nitrogen-doped porous phosphorus spheres for high-rate lithium storage

Phosphorus anode has shown great potential for the high-rate and high-energy–density lithium-ion batteries. Nevertheless, it still suffers from possible electrode cracking, ion-transport restrictions, and active-particle decomposition resulting from repeated alloying/de-alloying. To address the aforementioned issues, a nitrogen-doped flower-like porous phosphorus (f-P) sphere has been developed. The abundant micro-mesopores facilitate ion diffusion and enhance the internal bonding strength of the electrode. Concurrently, the doped nitrogen promotes the generation of a favorable solid electrolyte interphase constructed by fast-ion-conductors. As a result, the f-P exhibits a high-rate capacity of 735mAh g−1 at 20 A g−1 and maintains high Coulombic efficiencies over 900 cycles at 10 A g−1. Furthermore, coin full-cells comprising the f-P anode and lithium cobalt oxide cathode demonstrate stable operation at a high current density of 6 mA cm−2. The combination of a porous structure and doping strategy represents a viable approach for strengthening the durability of electrodes and optimizing the ion transport kinetics of advanced alloy anode materials.

Quantifying the Aging of Lithium-Ion Pouch Cells Using Pressure Sensors

Understanding the behavior of pressure increases in lithium-ion (Li-ion) cells is essential for prolonging the lifespan of Li-ion battery cells and minimizing the safety risks associated with cell aging. This work investigates the effects of C-rates and temperature on pressure behavior in commercial lithium cobalt oxide (LCO)/graphite pouch cells. The battery is volumetrically constrained, and the mechanical pressure response is measured using a force gauge as the battery is cycled. The effect of the C-rate (1C, 2C, and 3C) and ambient temperature (10 °C, 25 °C, and 40 °C) on the increase in battery pressure is investigated. By analyzing the change in the minimum, maximum, and pressure difference per cycle, we identify and discuss the effects of different factors (i.e., SEI layer damage, electrolyte decomposition, lithium plating) on the pressure behavior. Operating at high C-rates or low temperatures rapidly increases the residual pressure as the battery is cycled. The results suggest that lithium plating is predominantly responsible for battery expansion and pressure increase during the cycle aging of Li-ion cells rather than electrolyte decomposition. Electrochemical impedance spectroscopy (EIS) measurements can support our conclusions. Postmortem analysis of the aged cells was performed using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) to confirm the occurrence of lithium plating and film growth on the anodes of the aged cells. This study demonstrates that pressure measurements can provide insights into the aging mechanisms of Li-ion batteries and can be used as a reliable predictor of battery degradation.

Concentration Controlling of Carboxylic Ester-Based Electrolyte for Low Temperature Lithium-Ion Batteries.

Low temperature has been a major challenge for lithium-ion batteries (LIBs) to maintain satisfied electrochemical performance, and the main reason is the deactivation of electrolyte with the decreasing temperature. To address this point, in present work, we develop a low-temperature resistant electrolyte which includes ethyl acetate (EA) and fluoroethylene carbonate (FEC) as solvent and lithium difluoro(oxalato)borate (LiDFOB) as the primary lithium salt. Due to the preferential decomposition of LiDFOB and FEC, a solid electrolyte interface rich in LiF is formed on the lithium metal anodes (LMAs) and lithium cobalt oxide (LCO) cathodes, contributing to higher stability and rapid desolvation of Li+ ions. The batteries with the optimized electrolyte can undergo cycling tests at -40 °C, with a capacity retention of 83.9 % after 200 cycles. Furthermore, the optimized electrolyte exhibits excellent compatibility with both LCO cathodes and graphite (Gr) anodes, enabling a Gr/LCO battery to maintain a capacity retention of 90.3 % after multiple cycles at -25 °C. This work proposes a cost-effective electrolyte that can activate potential LIBs in practical scenarios, especially in low-temperature environments.

Structure, Composition and Electrochemical Properties of Disordered Rock-Salt LiCoO2 Thin Films Prepared by Ion Beam Assisted Deposition

Ion beam assisted deposition is a method used to deposit thin films while irradiating the growing film with an ion beam. This technique is known to be effective in crystallization and orientation control at low temperatures. In this study, LiCoO2 (LCO) thin films were prepared at temperatures below 100 °C using ion beam assisted pulsed laser deposition. The structure, composition, and electrochemical properties of these films were characterized. The results indicated that LCO thin films with a disordered rock salt structure and triaxial orientation were successfully grown on polycrystalline aluminum and quartz glass substrates using ion beam assisted deposition. Furthermore, the diffusion coefficient of Li ions and the charge/discharge capacity were significantly improved compared to LCO thin films with a disordered rock salt structure prepared without the ion beam assisted process.

Recommended Practices for the Electrochemical Recovery of Cobalt from Lithium Cobalt Oxide: A Case Study of the Choline Chloride:Ethylene Glycol Deep Eutectic Solvent.

We recommend best practices for the recovery of cobalt from LiCoO2 (LCO) lithium-ion battery (LIB) cathodes by (i) leaching using green deep eutectic solvents (DES) and (ii) subsequent electrodeposition, through a case study of the choline chloride (ChCl):ethylene glycol (EG) DES. DES physical properties (conductivity, viscosity, and surface tension) were tailored by varying the composition between mole ratios of 1:2 and 1:5 (ChCl:EG). Examined along with leaching process parameters (temperature, duration), increasing the fraction of hydrogen bond donors (HBDs) decreased DES surface tension and enhanced leaching. Complete Co recovery was achieved using1:5 ChCl:EG DES at 160oC and 48 hours. Leaching temperatures >160oC are discouraged due to DES thermal degradation. The electrodeposition process was optimized for selective Co recovery with high faradaic efficiency. The leaching ability of the DES was antithetical to the stability of electrodeposition cell components and required operational parameter adjustment to minimize degradation. The optimized system (copper cathode and stainless-steel anode) employing 1:5 DES leachate exhibited a faradaic efficiency of ~80 %, specific Co recovery of ~0.8 mg hr-1 cm-1 at 50 oC and evidence of uniform deposition. DES surface tension is a key descriptor of metal recovery, and guidelines are presented to maximize selective Co recovery.