Sulfur (S) encapsulated in porous carbon nanofibers (CNFs) was synthesized viaelectrospinning, carbonization and solution-based chemical reaction–deposition method. The chemical reaction–deposition strategy provides intimate contact between the S and the CNFs. This would not necessarily be the case for other reported methods, such as ball milling and thermal treatment. These novel porous carbon nanofiber–sulfur (CNF–S) nanocomposites with various S loadings showed high reversible capacity, good discharge capacity retention and enhanced rate capability when they were used as cathodes in rechargeable Li/S cells. We demonstrated here that an electrode prepared from a porous CNF–S nanocomposite with 42 wt% S maintains a stable discharge capacity of about 1400 mA h g⁻¹ at 0.05 C, 1100 mA h g⁻¹ at 0.1 C and 900 mA h g⁻¹ at 0.2 C. We attribute the good electrochemical performance to the high electrical conductivity and the extremely high surface area of the CNFs that homogeneously disperse and immobilize S on their porous structures, alleviating the polysulfide shuttle phenomenon. SEM measurements showed that the porous CNF structures remained nearly unchanged even after 30 cycles' discharging/charging at 0.05 C.

The kinetics of methanol electro‐oxidation on well‐characterized Pt‐Ru alloy surfaces were measured in sulfuric acid solution as a function of temperature. The alloy surfaces were prepared in ultrahigh vacuum with the surface composition determined by low energy ion scattering. It was found that the activity of Ru towards the dissociative adsorption of methanol is a strong function of temperature. This change in the adsorptive nature of the Ru sites with temperature produced a variation in the optimum surface composition with temperature. The optimum surface had an Ru content which increased with increasing temperature, from close to ≈10 atomic percent (a/o) Ru at 25°C to a value in the vicinity of ≈30 a/o at 60°C. The shift in optimum composition with temperature was attributed to a shift in the rate‐determining step from methanol adsorption/dehydrogenation at low temperature to the surface reaction between the dehydrogenated intermediate and surface oxygen at high temperature. The apparent activation energies were consistent with this change in the rate‐determining step.

In this review, we begin with a brief discussion of the operating principles and scientific/technical challenges faced by the development of lithium/sulfur cells. We then introduce some recent progress in exploring cathodes, anodes, and electrolytes for lithium/sulfur cells. In particular, several effective strategies used to enhance energy/power density, obtain good efficiencies, and prolong cycle life will be highlighted. We also discuss recent advancements in techniques for investigating electrode reactions in real time and monitoring structural/morphological changes of electrode materials under cell operating conditions to gain a better understanding of the mechanistic details of electrode processes. Finally, the opportunities and perspective for future research directions will be discussed.