Efficient Recovery of Lithium Cobaltate from Spent Lithium-Ion Batteries for Oxygen Evolution Reaction

Owing to technological advancements and the ever-increasing population, the search for renewable energy resources has increased. One such attempt at finding effective renewable energy is recycling of lithium-ion batteries and using the recycled material as an electrocatalyst for the oxygen evolution reaction (OER) step in water splitting reactions. In electrocatalysis, the OER plays a crucial role and several electrocatalysts have been investigated to improve the efficiency of O2 gas evolution. Present research involves the use of citric acid coupled with lemon peel extracts for efficient recovery of lithium cobaltate from waste lithium-ion batteries and subsequent use of the recovered cathode material for OER in water splitting. Optimum recovery was achieved at 90 °C within 3 h of treatment with 1.5 M citric acid and 1.5% extract volume. The consequent electrode materials were calcined at 600, 700 and 800 °C and compared to the untreated waste material calcined at 600 °C for OER activity. The treated material recovered and calcined at 600 °C was the best among all of the samples for OER activity. Its average particle size was estimated to be within the 20–100 nm range and required a low overpotential of 0.55 V vs. RHE for the current density to reach 10 mA cm2 with a Tafel value of 128 mV/dec.

Experimental process and kinetic behavior of carbothermal reduction of lithium cobaltate as a cathode for waste lithium batteries

Lithium cobaltate as a cathode material has great recycling value in the recycling process of spent lithium-ion batteries, To promote the thermal reduction process of lithium cobaltate and recover high-value cobalt and lithium metals, we studied the process of lithium cobaltate reduction by carbon under different conditions and its thermal reaction kinetics. The effects of calcination temperature, raw material ratio, pelletizing pressure and holding time on the reduction rate of lithium cobaltate were investigated by controlling variables. The results showed that the optimum experimental conditions were as follows: mass ratio of carbon and lithium cobaltate was 1:1, pelletizing pressure was 45 MPa, calcination temperature was 800 °C, and calcination time was 6 h. Under these conditions, lithium cobaltate could be converted into cobalt and lithium carbonate, and the recovery rate of cobalt and lithium was 97% and 95%, respectively. A kinetic study on the carbothermal reduction reaction of LiCoO2 showed that the average activation energy of the carbothermal reaction of LiCoO2 under nitrogen protection was 280.6851 kJ/mol, and the mechanism model of the thermal decomposition reaction of LiCoO2 was controlled by chemicals, showing a deceleration curve. The corresponding process conforms to the threedimensional diffusion mechanism of the inverse Jander equation, which lays a theoretical foundation for the high-efficiency separation and recovery of LiCoO2 cathode material for waste lithium-ion batteries.

Dimethyl trimethylsilyl phosphite as a novel electrolyte additive for high voltage layered lithium cobaltate-based lithium ion batteries

The addition of 0.5 wt.% of DMTMSP to the electrolyte could improve the low-temperature discharge and cycling performances of high voltage layered lithium cobaltate-based lithium ion batteries.

Review of Modified Nickel-Cobalt Lithium Aluminate Cathode Materials for Lithium-Ion Batteries

Ternary nickel-cobalt lithium aluminate LiNixCoyAl1‐x‐yO2 (NCA, x≥0.8) is an essential cathode material with many vital advantages, such as lower cost and higher specific capacity compared with lithium cobaltate and lithium iron phosphate materials. However, the noticeably irreversible capacity and reduced cycle performance of NCA cathode materials have restricted their further development. To solve these problems and further improve the electrochemical performance, numerous research studies on material modification have been conducted, achieving promising results in recent years. In this work, the progress of NCA cathode materials is examined from the aspects of surface coating and bulk doping. Furthermore, future research directions for NCA cathode materials are proposed.

SYNTHESIS AND ELECTRICAL PROPERTIES OF (Li, Ca)-SUBSTITUTED LANTHANUM COBALTATES

(Li, Ca)-substitute lanthanum cobaltates with composition La1-3xLixCа2xCoO3-δ (0≤x≤0.33) was synthesized by co-precipitation method of hydroxycarbonates. It is determined that the homogeneity region for the system La1-3xLixCа2xCoO3-δ is limited to the composition of x = 0.1. As in the case of Sr- and Ba-containing cobaltates, at x> 0.1, peaks on the diffractograms of the compounds correspond to the phase of lithium cobaltite Li1-yCoO2 with a layered structure. It turned out that the crystallographic parameters of orthorhombic Ca-containing cobaltates increases in comparison with the parameters of the unsubstituted LaCoO3. It is found that with an increase in the mean ion radius of the substituent in the region of homogeneity there is an increase in the average oxidation state of cobalt. The morphological characteristics of complex oxides were studied by using scanning electron microscopy. The grain sizes are in the range from 1 to 2 microns. In the photo along with the small grains you can notice enough large sintered particles in the size of 3 – 4 microns. Also, in SEM-photos, it is possible to detect the impurity phase of lithium cobaltate in the form of grains of the correct hexagonal form, which confirms the results of the X-Ray phase analysis. The 3d-hole (Co4+) formed by the adding of a small amount of Ca2+ and Li+ remains bound to adjacent closely spaced cobalt ions and acts as deep acceptor levels. With increasing substitution degree x, the acceptor complexes interact, forming an σ * conduction band. Due to this, at x≥0.3, the conductivity section of the semiconductor type disappears at the temperature dependence of the electric resistance and the conductivity begins to take a metallic character. On the other hand, contributing to the overall resistance of the system may introduce impurity phases, which is more likely, taking into account the results of the X-Ray phase analysis. It should also be noted that when the concentration of additives increases, the steepness of the curves ρ(Т) decreases.