A three-dimensional interconnected nitrogen-doped graphene-like porous carbon-modified separator for high-performance Li–S batteries

Abstract

Suppressing rapid capacity decay caused by the shuttle effect of dissolved lithium polysulfides between two electrodes is crucial to the realization of a practical lithium–sulfur (Li–S) batteries.

A Mott–Schottky Heterogeneous Layer for Li–S Batteries: Enabling Both High Stability and Commercial‐Sulfur Utilization

“…Apart from the larger Q L /Q H , the cell with RPM/PP separator shows a much higher commercial‐sulfur utilization than that of PP (3.8 times at 5 C) and most of the reported separator interlayers (Figure 2d). [ 38,45–48 ] These results suggest that the “reservoir” structure of RPM could effectively intercept polysulfides through strong chemical binding and spatially regulate the solid‐state Li 2 S deposition with enhanced deposition efficiency, and as a result, sulfur is reutilized more efficiently in the cell with RPM/PP separator.…”

“…As shown in the rate performance results, the cell with RPM/PP delivers highly reversible specific capacities of 1364, 1323, 1228, 1131, 1001, and 777 mAh g −1 at the rates of 0.1, 0.2, 0.5, 1, 2, and 5 C (1 C = 1675 mA g −1 ), respectively (the capacities are selected as the third cycle of each rate), which are superior to PP, MoS 2 /PP, RGO-PANI/PP, and most of the other reported interlayer materials (Figure 2b,c and Table S2, Supporting Information). [18,22,[37][38][39][40][41][42][43][44][45][46][47][48] Even at a much higher rate of 10 C, the discharge capacity of cells with RPM/PP can still maintain 553 mAh g −1 . The satisfactory rate performance can be attributed to the abundant exposure of MoS 2 and heterointerface active sites in RPM for LiPSs conversion.…”

“…To the best of our knowledge, such high-rate (5 C) cycle stability based on the commercial-sulfur cathode is superior to most of the reported LSBs (Figure 2g). [19,43,46,48,[53][54][55][56][57] Although the low temperature will slow down the LiPSs migration and inhibit the catalytic effect of active component in sulfur conversion, the cell with RPM/PP delivers a high initial discharge capacity of 941.2 mAh g −1 even at −20 °C, which can still maintain at 717.8 mAh g −1 after 150 cycles at 0.5 C with a capacity retention of 56.2% (Figure S12, Supporting Information). [58] Furthermore, a high sulfur utilization of 56.2% can also be achieved under such harsh temperature conditions, demonstrating the strong catalytic and utilization ability of the RPM layer for LiPSs.…”