Influence of working temperature on the electrochemical characteristics of Al2O3-coated LiNi0.8Co0.1Mn0.1O2 cathode materials for Li-ion batteries

Correlating Morphological and Structural Evolution with the Electrochemical Performance of Nickel-Rich Cathode Materials: From Polycrystal to Single Crystal

“…The results strongly demonstrate that the reduction reaction at 3.55 V significantly affects the discharge capacity, and the capacity loss here is the main factor causing the different discharge capacities. At 45 °C, the discharge capacity of each sample increased as higher operating temperatures could improve the lithium-ion diffusion coefficient (D Li + ) value, 43 which is reflected in a further raised peak at 3.55 V in the dQ dV −1 curve, like that observed at 25 °C.…”

Enhanced Electrochemical Performance and Thermal Stability of ZrO2- and rGO–ZrO2-Coated Li[Ni0.8Co0.1Mn0.1]O2 Cathode Material for Li-Ion Batteries

“…The significant increase in R ct and R sf of the pristine material after 100 cycles greatly increases the kinetic barrier for reversible lithium extraction/insertion, thereby leading to fast capacity degradation . The lower R ct and R sf values of the ZrO 2 -coated cathode after 100 cycles indicate the impact of ZrO 2 coating on preventing cathode degradation and maintaining the structure. , The composite-coated cathode exhibits superior performance by comparing all electrodes; the least R ct and R sf at all cycles and temperatures are due to improvement of electrical conductivity and reduction in electrode polarization by rGO nanosheets and restriction of the harmful side reactions by ZrO 2 NPs. ,, It is worth mentioning that after 100 cycles, the R sf value of each electrode increases with an increase of temperature, which stems from catalyzed HF attack and accumulation of side reaction products on the surface of cathode electrodes. , The R ct value of all electrodes has decreased compared to their room temperature values by increasing the temperature to 55 °C, which can be explained in eq The Li ion diffusion coefficient ( D Li ) of the cathode materials are calculated based on eq and summarized in Table S2. In the above formula, R is the gas constant, T denotes the absolute temperature, A c signifies the cathode surface, C Li is the lithium ion concentration, F is the Faraday constant, and σ is the Warburg coefficient, which obeys the following relationship (eq )­ The slope of Z ′ vs ω –1/2 in Figure b,d,f,h reflects the σ w . The calculated values of D Li are in the range of 10 –14 to 10 –13 cm 2 s –1 , which are in agreement with the literature. ,, At 55 °C, the D Li of the pristine NCM811 after 100 cycles significantly decreases and is approximately 11 times smaller than that of the first cycle; however, for the ZrO 2 - and composite-coated cathodes, D Li has decreased by 1.9 and 1.8 times, respectively.…”

Double Conductor Coating to Improve the Structural Stability and Electrochemical Performance of LiNi0.8Co0.1Mn0.1O2 Cathode Material

“…15−20 Since the coating acts as a physical separation defense between the electrode and electrolyte, the coating should be chemically stable to prevent the coating from being destroyed at high potentials, as well as exhibit good ionic and electronic conductivity, which contributes to Li + migration and e − conduction. The common coating materials mainly include inert compounds such as metal oxides, 21,22 metal fluorides, 23,24 and metal phosphates, 25,26 as well as conductive materials such as lithium-containing compounds 27,28 (CPs). 29,30 In addition, graphene and carbon materials 31,32 are also used.…”

“…Since the coating acts as a physical separation defense between the electrode and electrolyte, the coating should be chemically stable to prevent the coating from being destroyed at high potentials, as well as exhibit good ionic and electronic conductivity, which contributes to Li + migration and e – conduction. The common coating materials mainly include inert compounds such as metal oxides, , metal fluorides, , and metal phosphates, , as well as conductive materials such as lithium-containing compounds , and conductive polymers (CPs). , In addition, graphene and carbon materials , are also used. Although inert compounds have stable chemical properties, they impede the conduction of lithium ions and electrons, leading to poor electrical conductivity of materials, which will affect the ability of batteries at fast charge and discharge rates.…”