Silica/polyurea hybrid microcapsules loaded with hexamethylene diisocyanate (HDI) as core materials were prepared via a combined strategy of interfacial polymerization and an in situ sol–gel process in an oil-in-water emulsion. They were clearly characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. The resultant microcapsules have diameters of 57–328 μm, shell thicknesses of 1–8 μm, and core fractions of 51.2–65.6%. The diameter and shell thickness were linearly related to the agitation rate in the double logarithm coordinates, and the core fraction were linearly related to the agitation rate, indicating that the structure and component of the microcapsules can be controlled effectively. The resistant properties against thermal and solvent attacks were assessed by using thermogravimetric analysis and titration. The results show that the microcapsules had outstanding thermal stability with initial evaporation temperature (defined at 5% of weight loss), increased by around 58 °C compared with that of pure core material, and good resistance to xylene with less than 25.9 ± 0.7 wt% reduction of core content after immersion for 100 h. Self-healing anticorrosion coatings based on microcapsules were fabricated on a steel substrate. Preliminary results indicated significant corrosion retardancy occurred in the coatings under an accelerated corrosion process, showing the great potential of our microcapsules in the development of catalyst-free, one-part, self-healing coatings for corrosion control.

Growing market demand from portable electronics to electric automobiles boosts the development of lithium-ion batteries (LIBs) with high energy density and rate performance. However, strong solvation effect between lithium ions (Li⁺) and solvent molecules in common electrolytes limits the mobility of Li⁺ ions in electrolytes. Consequently, anions dominate the charge conduction in electrolytes, and in most cases, the value of Li⁺ transference number (T⁺) is between 0.2 and 0.4. A low T₊ will aggravate concentration polarization in the process of charging and discharging, especially at high rate, which not only increases the overpotential but also intensifies side reactions, along with uneven deposition of lithium (Li) and the growth of lithium dendrites when lithium metal is used as anode. In this review, promising strategies to improve T₊ in liquid electrolytes would be summarized. The migration of Li⁺ ions is affected directly by the types and concentration of lithium salts, solvents, and additives in bulk electrolytes. Besides, Li⁺ ions will pass through the separator and solid electrolyte interphase (SEI) when transferring between anodes and cathodes. With this in mind, we will classify and summarize threads of enhancing T₊ from five aspects: lithium salts, solvents, additives, separators, and SEI based on different mechanisms, including covalently bonding, desolvation effect, Lewis acid-base interaction, electrostatic interaction, pore sieving, and supramolecular interaction. We believe this review will present a systematic understanding and summary on T₊ and point out some feasible threads to enhance battery performance by enhancing T₊.

Donor number plays an essential role in deciding lithium salt solubility and the Li ⁺ solvation structure, thus influencing the electrode interphase, reaction pathways and kinetics in lithium metal batteries.