Natural Integrated Carbon Architecture for Rechargeable Lithium–Sulfur Batteries

Natural integrated carbon architecture cathodes without any additives, which were derived from the bark of plane trees, have highly loaded sulfur of 3.2–4.2 mg cm^–2. The as-obtained carbon slice has an integrated architecture with micropore-to-macrospore distribution and a large surface area of 528 m² g^–1. As a result, the integrated carbon–sulfur cathode exhibited an initial discharge capacity of 1159 mA h g^–1 at 0.2 A g^–1 for a lithium–sulfur battery. Even after 60 cycles, a high specific capacity of 608 mA h g^–1 with a high Coulombic efficiency (>98%) was retained, much better than MWCNTs-based electrodes and macropore-destroyed carbon slices

Ultrathin Wrinkled N‑Doped Carbon Nanotubes for Noble-Metal Loading and Oxygen Reduction Reaction

We describe the fabrication of ultrathin wrinkled N-doped carbon nanotubes by an in situ solid-state method. The positions of Co catalyst were first labeled by good-dispersion and highly loaded Au and Pt, indicating the most of Co are unsealed. The resultant unique nanoarchitecture, which exhibits the features of carbon nanotube and graphene with a combined effect of 1D and 2D carbon-based nanostructures, exhibited a superior ORR activity to carbon nanotubes and graphene. Moreover, the novel catalysts showed a better durability and higher tolerance to methanol crossover and poisoning effects than those of Pt/C

Mechanism on the Improved Performance of Lithium Sulfur Batteries with MXene-Based Additives

The loss of sulfur in the cathode of a lithium sulfur battery (LSB) severely hinders the practical application of LSBs, and so do the insulativity of S and its lithiation end products. The incorporation of MXene can significantly improve the performance of LSBs; however, the underlying mechanism at the atomic scale has not been deeply explored. In the present work, by using density functional theory calculations, we systemically studied the interactions of lithium (poly)­sulfides (Li₂S_<i>m</i>) on Ti-based bare MXenes (Ti_<i>n</i>X_<i>n</i>–1) and surface functionalized Ti₂C with −F, −O, and −OH groups. Through analyzing the geometric and electronic structures, binding energies, and deformation charge densities of Li₂S_<i>m</i> adsorbed MXenes, we found that the strong Ti–S bonds dominate the interactions between Li₂S<i>_m</i> and MXenes. The strong Coulombic interactions help cathodes to confine S from dissolution. Besides, the conductivities of MXenes and Li₂S<i>_m</i>@MXenes are beneficial for the overall performance of the LSB. These will provide in-depth theoretical guidance support for the utilization of MXene in LSBs