Enabling a Stable Room-Temperature Sodium–Sulfur Battery Cathode by Building Heterostructures in Multichannel Carbon Fibers

Abstract

Room-temperature sodium−sulfur (RT Na−S) batteries are widely considered as one of the alternative energystorage systems with low cost and high energy density. However, the both poor cycle stability and capacity are two critical issues arising from low conversion kinetics and sodium polysulfides (NaPSs) dissolution for sulfur cathodes during the charge/discharge process. Herein, we report a highly stable RT Na−S battery cathode via building heterostructures in multichannel carbon fibers. The TiN-TiO 2 @MCCFs, fabricated by electrospinning and nitriding techniques, are loaded with the active material S, forming S/TiN-TiO 2 @MCCFs as the cathode in a RT Na−S battery. At 0.1 A g −1 , the cathode produces the capacity of more than 640 mAh g −1 within 100 cycles with a high Coulombic efficiency of nearly 100%. Even at 5 A g −1 , the battery still exhibites a capacity of 257.1 mAh g −1 after 1000 cycles. Combining structural and electrochemical analyses with the first-principles calculations reveals that the incorporation of the highly electrocatalytic activity of TiN with the powerful chemisorption of TiO 2 well stabilizes S and also alleviates the shuttle effects of polysulfides. This work with simple processes and low cost is expected to promote the further development and application of metal−S batteries.

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

“…Furthermore, Zheng et al built a multichannel carbon fibers host with the highly electrocatalytic activity of TiN and powerful chemisorption of TiO 2 to stabilize S (S/TiN-TiO 2 @MCCFs) (Figure 6d), in which TiO 2 could powerfully trap Na-polysulfides and speedily transport them to TiN surface for electrocatalytic deposition via the TiN-TiO 2 interface (Figure 6e). [32] therefore, this cathode with TiN-TiO 2 heterostructures could effectively improve the trapping ability and conversion rate of Na-polysulfides. Even When cycled at a high rate of 5 A g À 1 , the battery still shows a capacity of 257.1 mAh g À 1 after 1000 cycles.…”

“…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…”

“…Reproduced from ref. [32] with permission from American Chemical Society. ) cycling performances of core-shell ZCS@S, ZnS@S and CoS 2 @S at 1.0 A g À 1 , c) photographs (inset) and UV-vis spectra of the Na 2 S 4 solution before and after exposure to CoS 2 , ZnS, and ZCS, (d) XPS spectra of coreÀ shell ZCS@S in S 2p region during charged and discharged at different voltages.…”

“…d) Schematic of the design principle of the TiN-TiO 2 heterostructure, e) mechanism illustrations of Na 2 S x adsorption-conversion. Reproduced from ref [32]. with permission from American Chemical Society.…”

Status and Challenges of Cathode Materials for Room‐Temperature Sodium–Sulfur Batteries

“…In addition, as shown in Figure 9e, Zheng and coworkers [ 44 ] reported the unique TiN–TiO 2 heterostructures with impressive adsorption–diffusion–catalysis effects in situ wrapped in the multichannel porous carbon matrix as sulfur host for RT Na–S batteries (TiN–TiO 2 @MCCFs). Clear lattice interface between TiN and TiO 2 is clearly visible in the HRTEM images.…”