Electrocatalyzing S Cathodes via Multisulfiphilic Sites for Superior Room-Temperature Sodium–Sulfur Batteries

Abstract

Room-temperature sodium–sulfur (RT-Na/S) batteries hold great promise for sustainable and cost-effective applications. Nevertheless, it remains a great challenge to achieve high capacity and cycling stability due to the low activity of sulfur and the sluggish conversion kinetics between polysulfide intermediates and sodium sulfide. Herein, an electrocatalyzing S cathode is fabricated, which consists of porous core–shell structure and multisulfiphilic sites. The flexible carbon structure effectively buffers volume changes during cycling and provides enclosed spaces to store S8 with exceptional conductivity. Significantly, the multisulfiphilic sites (ZnS and CoS2) enhance catalysis toward multistep S conversion, which effectively suppresses long-chain polysulfides dissolution and improves the kinetics of short-chain polysulfides. Thus, the obtained S cathodes achieve an enhanced cycling performance (570 mAh g–1 at 0.2 A g–1 over 1000 cycles), decent rate capability (250 mAh g–1 at 1.0 A g–1 over 2000 cycles), and high energy density of 384 Wh kg–1 toward practical applications.

Room‐Temperature Sodium–Sulfur Batteries and Beyond: Realizing Practical High Energy Systems through Anode, Cathode, and Electrolyte Engineering

“…In summary, polysulfide dissolution should be prioritized as the more critical issue, while electronic conductivity can be simply compensated for using conventional additives. In light of these findings, we could also speculate that for existing polar host materials such as N,O,S‐doped carbons demonstrated in Na–S batteries, [ 11,13,139–141,143,201,204 ] extensive doping could potentially improve sulfur‐trapping and battery cycle life further, regardless that it comes at the expense of electronic conductivity.…”

“…A few other transition metal sulfides were also proven as effective electrocatalysts, including NiS 2 nanocrystals and ZnS–CoS 2 crystals. [ 139,140 ] It should also be emphasized that the latter benefits from both high stability of ZnS and the good polysulfide suppression character of CoS 2 , achieving outstanding cycling performance. The ZnS–CoS 2 cathode showed an extremely long cycling life with a capacity of 570 mAh g −1 at 0.2 A g −1 over 1000 cycles.…”

“…Current estimates of Na–S battery gravimetric energy densities have been reported over a large range from around 380 to over 1000 Wh kg −1 , based only on the cathode weight. [ 13,140,141,184,238 ] A 2019 report exploited the porous nature of a carbon cloth current collector for a Na polysulfide cathode, reaching a high 946 Wh kg −1 based on the combined mass of sulfur and Na, and maintained a respectable 728 W h kg −1 after 500 cycles. [ 239 ] Liu et al.…”

Template‐Free Self‐Caging Nanochemistry for Large‐Scale Synthesis of Sulfonated‐Graphene@Sulfur Nanocage for Long‐Life Lithium‐Sulfur Batteries

“…The capacity decay is only 0.019% per cycle, and even when the sulfur loading is as high as 3.67 mg, after 1240 cycles at 1 C, the SG@S‐1:7 electrode also retains a relative high capacity of 500 mAh g –1 (Figure 3e). Compared to literature reports on similar structure, [ 13,14,18–20,52–64 ] the SG@S composite delivered excellent stable cycling stability.…”

Advanced High‐Performance Potassium–Chalcogen (S, Se, Te) Batteries

“…Host materials with electrocatalysis function can facilitate long‐chain polysulfides to rapidly convert into discharge/charge products before they are dissolved into electrolyte so that shuttle effect is suppressed from the root. Currently, many kinds of catalytic materials have been discovered in Li/Na–S batteries, such as metal Co, [ 72b ] Co 9 S 8 , [ 74a ] CoS 2 , [ 92 ] TiN, [ 93 ] and Co 3 S 4 , [ 94 ] which usually exhibit strong absorption capability as well. To improve the reaction kinetic and promote the conversion of polysulfides in Li–S batteries, Dai et al.…”