Reducing polarization of lithium-sulfur batteries via ZnS/reduced graphene oxide accelerated lithium polysulfide conversion

Atomic Tungsten on Graphene with Unique Coordination Enabling Kinetically Boosted Lithium–Sulfur Batteries

“…In view of the enhanced catalytic performance and favorable chemical interaction with LiPSs,t he W/NG is applied as amultifunctional modifier of coin-type Li-S cells to further understand its catalytic advantages.T ypically,t he cathode was fabricated by acetylene black/sulfur composite with as ulfur loading of 1.1 mg cm À2 .A se xhibited in Figure 4a,t he battery based on the W/NG@PP delivers ah igh initial discharge capacity of 1389 mAh g À1 at 0.2 C( 1C= 1672 mAh g À1 ), which is much higher than that of NG@PP (1299 mAh g À1 )and PP (1128 mAh g À1 )based batteries.After 200 cycles at 0.5 C, the W/NG@PP based battery remains ahigh capacity of 986 mAh g À1 ,corresponding to adecay rate of 0.1 %p er cycle.I ns harp contrast, the NG@PP and PP based batteries deliver inferior cycling performance with residual reversible capacities of 778 and 544 mAh g À1 ,r espectively.The enhanced capacity retention resulting from W/ NG@PP confirms that the inactivation and sluggish redox kinetics of sulfur species are dramatically addressed by the unique W-O 2 N 2 -C moiety with strong polysulfide interactions and electrocatalysis effects.I ts hould be noted that, some implicit information is contained in the charging/discharging behavior of batteries, [31][32][33] which can be employed to deeply analyze the catalytic performance of W/NG (Figure 4b and c TheL i-S chemistry with am ultistep electrochemical process including av ariety of intermediate species,a nd the charge transfer resistance (R ct )a td ifferent solid-liquid-solid conversion stages can effectively respond to the changes in kinetic properties. [34][35][36] As displayed in Figure S12, the ex-situ EIS spectra of the W/NG@PP and NG@PP based cells are recorded. It can be seen that, there is appreciable decrease for both R ct with the discharging going, which is related to the electrode activation process and the reduction of insulating S species.Inthe subsequent charging process,aslight decrease and then increase for the R ct happen attributed to the consumption of Li 2 Sa nd the final regeneration of sulfur.I t is worth noting that the R ct for the W/NG@PP based cell is always lower than that of NG@PP case during the whole charging/discharging process,verifying an optimized electron/ ion conductivity and favorable solid-liquid-solid conversion kinetics with the assistance of W-O 2 N 2 -C moiety.…”

Sandwiched Cathodes Assembled from CoS2‐Modified Carbon Clothes for High‐Performance Lithium‐Sulfur Batteries

“…To overcome the above‐mentioned issues and improve the electrochemical performance of LSBs, many efforts have been devoted to developing advanced sulfur hosts and multifunctional separators. [ 17 , 18 , 19 , 20 , 21 , 22 , 23 ] The carbonaceous materials, such as mesoporous carbon (CMK‐3), [ 24 , 25 ] reduced graphene oxide, [ 26 , 27 ] carbon nanotubes, [ 28 , 29 ] multichannel fibers, [ 30 , 31 , 32 ] were adopted as advanced sulfur hosts to reduce the capacity fading. These carbon‐based host materials typically have essential characteristics of high electronic conductivity, large specific surface area, and porous structures, which can improve the conductivity, realize high sulfur loading and reduce the influence of volumetric expansion.…”

Achieving Cycling Durability of Lithium–Sulfur Batteries via Capturing Polysulfides through a Three-Dimensional Interconnected Carbon Network Anchored with Ultrafine FeS Nanoparticles

“…Furthermore, it can be seen that the 3DC-FeS-650 interlayer could aid in reducing the electrochemical polarization according to the potential difference plots shown in Figure S10d. 38 To further verify the advantages of the 3DC-FeS-650 interlayer, the specific capacity contributions of the high potential stage and the low potential stage denoted as Q1 and Q2 are shown in Figure 3e (the tenth cycle at each current rate is taken). Theoretically, the Q2/Q1 ratio is 3 based on the theoretical specific capacity of two discharging stages.…”