Efficient Catalytic Conversion of Polysulfides by Biomimetic Design of “Branch-Leaf” Electrode for High-Energy Sodium–Sulfur Batteries

Abstract

Rechargeable room temperature sodium–sulfur (RT Na–S) batteries are seriously limited by low sulfur utilization and sluggish electrochemical reaction activity of polysulfide intermediates. Herein, a 3D “branch-leaf” biomimetic design proposed for high performance Na–S batteries, where the leaves constructed from Co nanoparticles on carbon nanofibers (CNF) are fully to expose the active sites of Co. The CNF network acts as conductive “branches” to ensure adequate electron and electrolyte supply for the Co leaves. As an effective electrocatalytic battery system, the 3D “branch-leaf” conductive network with abundant active sites and voids can effectively trap polysulfides and provide plentiful electron/ions pathways for electrochemical reaction. DFT calculation reveals that the Co nanoparticles can induce the formation of a unique Co–S–Na molecular layer on the Co surface, which can enable a fast reduction reaction of the polysulfides. Therefore, the prepared “branch-leaf” CNF-L@Co/S electrode exhibits a high initial specific capacity of 1201 mAh g−1 at 0.1 C and superior rate performance.

Electrolytes/Interphases: Enabling Distinguishable Sulfur Redox Processes in Room‐Temperature Sodium‐Sulfur Batteries

“…Reproduced with permission. [ 120 ] Copyright 2021, Springer Nature. f) Schematic illustration of CS bonds confining polysulfide to prevent dissolution.…”

“…[ 38 ] Besides, Xu's group recently designed a 3D branch‐leaf biomimetic cathode, where the leaf was composed of Co nanoparticles and carbon nanofibers (Figure 9e). [ 120 ] The carbon nanofibers functioned as conductive matrix, which improved electron and electrolyte supply for the Co. A unique Co‐S‐Na molecular layer was formed via chemical adsorption, which enabled a fast reduction reaction of the polysulfides. Moreover, other catalysts, including FeS 2 and NiS 2 as well as atomic metals, have been successfully applied in the C/S cathode and show promise for applications.…”

Recent Advances of Catalytic Effects in Cathode Materials for Room‐Temperature Sodium‐Sulfur Batteries

“…Year/Ref Single metal electrocatalysts 80 wt % S@Co/C/rGO 10 wt % CB 10 wt % PVDF Co 37.5 % PFSA-Na in DMF and 1 M NaClO 4 in EC/DEC 0.5 C, 484.9-226 (1000) [18] Co@NPCNFs/S Co 38 w% 1 M NaClO 4 in EC/DEC 0.1 C, 905.6-843 (100) [19] CNF-L@Co/S Co 45 % 1 M NaClO 4 in EC/DEC 0.1 C, 1201-~700 (180) [20] S@Ni-NCFs Ni 36 % 1 M NaClO 4 in TEGDME 1 C, 431-233 (270) [21] 70 wt % CN/Au/S) 20 wt % super-P 10 wt % CMC Au 56.5 wt % 1 M NaClO 4 in PC/FEC 0.1 A g À 1 , 1967-701 (110) [22] Metal-based compound electrocatalysts 70 wt % NiS 2 @NPCTs/S 20 wt % CB 10 wt % CMC NiS 2 56 % 1 M NaClO 4 in EC/PC/FEC 1 A g À 1 , 960-401 (750) [23] 70 wt % CoNC@S 20 wt % TIMCAL 10 wt % CMC CoS -1 M NaFSI in DEC/BTFE 0.08 A g À 1 , 1095-500 (150) [24] 70 wt % CoS 2 /NC/S-3 15 wt % AB 15 wt % CMC CoS 2 50.7 wt % 1 M NaSO 3 CF 3 in DOL/DME 0.1 A g À 1 , 944-488 (100) [25] 70 wt % FeS 2 @NCMS/S 20 wt % CB 10 wt % CMC FeS 2 65.5 wt % 1 M NaClO 4 in PC/EC/FEC 0.1 A g À 1 , 1471-524 (300) [26] 80 wt % S/MoS 2 /NCS 10 wt % super-P 10 wt % CMC MoS 2 43.8 wt % S and Na 2 S 6 in DME 0.5 A g À 1 , 1397.4-590.6 (200) [27] 75 wt % MoO 3 @PCNT/S 15 wt % AB 10 wt % CMC MoO 3 50 wt % 1 M NaClO 4 in EC/PC 0.5 A g À 1 , 465-208 (1000) [28] 80 wt % rGO/VO 2 /S 10 wt % CB 10 wt % PVDF VO 2 40 wt % 1 M NaClO 4 in TEGDME 0.2 C, 876.4-400 (200) [29] 70 wt % S@CoP-Co/ NCNHC 20 wt % CB 10 wt % CMC CoP 53 wt % 1 M NaClO 4 in PC/EC/FEC 0.1 A g À 1 , 1101-592 (220) [30] VC-CNFs@S VC 42 wt % 1 M of NaPF 6 in DME/DOL 0.5 C, ~394-379 [31] S/TiN-TiO 2 @MCCFs TiN ~57 % 1 M NaClO 4 in EC/PC/FEC 0.1 A g À 1 , 1308.2-640.4 (100) [32] 85 wt % S@CB@AlOOH 15 wt % sodium-alginate AlOOH 44.3 wt % 1 M NaClO 4 and 0.2 M NaNO 3 in TEGDME 0.2 C, 668-554.4 (50) [33] Multifunctional hybrid electrocatalysts 80 wt % S@Ni/Co-C-12 10 wt % CB 10 wt % PVDF Ni and Co 41.4 % 1 M NaClO 4 in TEGDME 0.5 C, 1229.3-793.8 (200) [34] 80 wt % ZCS@S 10 wt % CB 10 wt % CMC ZnS and CoS 2 57 wt % 1 M NaClO 4 in DEC/EC/FEC 0.2 A g À 1 , ~1950-570 (1000) [35] 80 wt % Co 1 -ZnS/C@S 10 wt % CB 10 wt % CMC Co 1 and ZnS 65 wt % 1 M NaClO 4 in DEC/EC/FEC 0.1 A g À 1 , ~1650-640 (500) [36] 70 wt % FCNT@Co 3 C-Co/S 20 wt % AB 10 wt % CMC FCNT and Co 3 C-Co ~77 wt % 1 M NaClO 4 in EC/DEC 0.5 C, ~910-~800 (100) [37] [a] rGO: reduced graphene oxide, CB: carbon black, AB: acetylene black, PVDF: polyvinylidene fluoride, NPCNFs: N-doped porous carbon nanofibers, CNF-L: "branch-leaf"-structural carbon nanofiber, NCFs: N-doped carbon fibers, CN: N-doped…”

“…Besides, other studies on nano-Co electrocatalysts for S cathodes also achieved enhanced performances. [19][20] Furthermore, metallic Ni and Au have been loaded on carbon hosts as electrocatalysts for decent-performance RT-Na/ S batteries. Guo et al fabricated a 3D network S cathode of Ni hollow spheres and N-doped carbon fibers (Ni-NCFs) as illustrated in Figure 3a, which showed a capacity of 431 mAh g À 1 at 1 C. [21] The introduction of Ni not only could catalyze the Napolysulfide conversion and enhance electronic conductivity (Figure 3b-c), but also could be polarized to form polar NiÀ S bonds, anchoring mobile polysulfides through chemisorption.…”

Anthozoan-like porous nanocages with nano-cobalt-armed CNT multifunctional layers as a cathode material for highly stable Na–S batteries

“…Accordingly, many polar material composites, such as oxides (TiO 2 , 12,13 15,16 CoS, 17 NiCo 2 S 4 , 18 VS 2 , etc. ), selenides (NiSe 2 19 ) and transition metals (Co, 20 Ni/Co, 21 etc. ), have been introduced into cathode materials to inhibit the polysulfide shuttle effect by forming a strong chemical affinity between transition metal elements and polysulfides.…”