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In this research, we systematically examine the impact of atomic cation dopants and metal oxide coatings, including their respective oxidation states, on the electrochemical performance of Ni-rich NCA90 cathode materials. The study reveals that dopants exhibiting varied oxidation states, derived from high annealing temperatures, can efficaciously mitigate H2–H3 phase transitions, thereby amplifying the structural stability of the materials. Complementary Density Functional Theory (DFT) calculations corroborate that a judiciously selected dopant can enhance the electronic attributes of the cathode materials. Notably, the incorporation of a tungsten dopant is found to markedly modulate the kinetics of lithium transfer throughout the battery cycling process. This research provides vital insights into the role of cation dopants and metal oxide coatings in optimizing the electrochemical performance of Ni-rich cathode materials. [ABSTRACT FROM AUTHOR]

Li–S batteries with a sulphur loading content of 5 mg cm−2 were produced as large-scale 18 650 cylindrical cells. We have found that a key failure mode of cylindrical Li–S battery cells is the severe capacity fading during the galvanostatic charge–discharge process due to the corrosion of the electrodes, the electrolyte decomposition, and the severe polysulphide shuttling effect. [ABSTRACT FROM AUTHOR]

There is a controversial issue based on the particle cracking of the Ni-rich layered oxide cathode materials whether it occurs at the primary particles or the grain boundary. Herein, we found that the microcracking of NMC811 does not occur at single crystalline primary particles even abused at a severe upper cell voltage of 4.7 V having a lot of gas evolution since the single-crystal NMC811 has superior mechanical stability. The capacity retentions determined at 1C rate and a 100% state of charge (SOC) are 80% and 50% after 1000 cycles for single crystal and polycrystal NMC811, respectively. [ABSTRACT FROM AUTHOR]

The safety of Li-ion batteries is one of the most important factors, if not the most, determining their practical applications. We have found that free carbonate-based solvent molecules in the hybrid electrolyte system can cause severe safety concerns. Mixing ionic liquids with a carbonate-based solvent as the co-solvent at a fixed salt concentration of 1 M LiPF6 can lead to free carbonate-based molecules causing poor charge storage performance and safety concerns. [ABSTRACT FROM AUTHOR]

Transport phenomena and the solvation structure of lithium ions (Li+) and hexafluorophosphate anions (PF6−) in electrolytes with different fluoroethylene carbonate (FEC) concentrations as well as the electrochemical performance and safety of Ni-rich Li-ion battery cells at the 18650 cylindrical cell level are investigated. We have found that the electrolyte with an optimized FEC concentration (25% v/v) can effectively enhance the transport property in terms of the Li+ transference number and contact ion pair (CIP) ratio leading to high performance and safety of practical 18650 cylindrical LIBs. [ABSTRACT FROM AUTHOR]

The interaction between the reactive lithium metal surface and LiNO3 results in the formation of LixNOy clusters, which can protect the Li metal anode and suppress the shuttling effect of lithium polysulfides via the dipole–dipole interaction called the lithium bond. [ABSTRACT FROM AUTHOR]