3D, Mutually Embedded MOF@Carbon Nanotube Hybrid Networks for High‐Performance Lithium‐Sulfur Batteries

Abstract

Metal‐organic frameworks (MOFs) hybridized with a conductive matrix could potentially serve as a sulfur host for lithium‐sulfur (Li‐S) battery electrodes; so far most of the previously studied hybrid structures are in the powder form or thin compact films. This study reports 3D porous MOF@carbon nanotube (CNT) networks by grafting MOFs with tailored particle size uniformly throughout a CNT sponge skeleton. Growing larger‐size MOF particles to entrap the conductive CNT network yields a mutually embedded structure with high stability, and after sulfur encapsulation, it shows an initial discharge capacity of ≈1380 mA h g−1 (at 0.1 C) and excellent cycling stability with a very low fading rate. Furthermore, owing to the 3D porous network that is suitable for enhanced sulfur loading, a remarkable areal capacity of ≈11 mA h cm−2 (at 0.1 C) is obtained, which is much higher than other MOF‐based hybrid electrodes. The mutually embedded MOF@CNTs with simultaneously high specific capacity, areal capacity, and cycling stability represent an advanced candidate for developing high‐performance Li‐S batteries and other energy storage systems.

Natural Okra Shells Derived Nitrogen‐Doped Porous Carbon to Regulate Polysulfides for High‐Performance Lithium–Sulfur Batteries

“…The CV curve of Super P/S shows that two broad cathodic peaks (I and II) at 2.26 and 2.01 V in the reduction process correspond to the transformation from long‐chain S 8 to short‐chain Li 2 S x ( x = 4 or 3) and then transfer to the precipitated Li 2 S x ( x = 1 or 2), respectively. In the reverse oxidization process, two anodic peaks (III and IV) at 2.35 and 2.41 V correspond to the reversible conversion process from solid Li 2 S x ( x = 1 or 2) to short‐chain Li 2 S x ( x = 3 or 4) and then to long‐chain Li 2 S 8 or S 8 , respectively . The CV curves of OSC/S and N‐OSC/S display similar shape.…”

Dual Dopamine Derived Polydopamine Coated N‐Doped Porous Carbon Spheres as a Sulfur Host for High‐Performance Lithium–Sulfur Batteries

“…Two representative cathodic peaks at 2.25 and 2.0 V can be observed, corresponding to the solid (S 8 ) to liquid (high order Li 2 S x , 4≤ x ≤8) phase transition and the further reduction of soluble polysulfides to solid‐state products (Li 2 S 2 /Li 2 S). In the subsequent anodic scan, the sharp oxidation peak at around 2.43 V corresponds to the reverse reaction . At a low rate of 0.1 C, the NPC/S cathode exhibits a higher initial specific capacity (1363 mAh g −1 ) than the NPC/S@PDA cathode (1290 mAh g −1 ), which is possible due to larger charge‐transfer resistance (Figures S5 and S6 in the Supporting Information).…”

Hierarchically Designed CNF/S−Cu/CNF Nonwoven Electrode as Free‐Standing Cathode for Lithium−Sulfur Batteries

“…Figure 4a shows the initial cyclic voltammetric (CV) curves of the CNF/SÀCu/CNF electrode in the potential range of 1.5-3.0 V. Two distinct cathodic peaks appear at 2.4 and 2.0 V associate with the transition from S 8 to soluble higher order polysulfides (Li 2 S x , 4 x 8). [41] In the subsequent anodic process, oxidation peaks are observed at 2.1, 2.4 and 2.6 V, which are attributed to the reverse phase transition from Li 2 S to polysulfides and finally to sulfur. [41] In the subsequent anodic process, oxidation peaks are observed at 2.1, 2.4 and 2.6 V, which are attributed to the reverse phase transition from Li 2 S to polysulfides and finally to sulfur.…”