Thermodynamics and Kinetics of Sulfur Cathode during Discharge in MgTFSI2–DME Electrolyte

Rechargeable magnesium/sulfur battery is of significant interest because its energy density (1700 Wh kg^?1 and 3200 Wh L^?1) is among the highest of all battery chemistries (lower than Li/O₂ and Mg/O₂ but comparable to Li/S), and Mg metal allows reversible operation (100% Coulombic efficiency) with no dendrite formation. This great promise is already justified in some early reports. However, lack of mechanistic study of sulfur reaction in the Mg cation environment has severely hindered our understanding and prevents effective measures for performance improvement. In this work, the very first systematic fundamental study on Mg/S system is conducted by combining experimental methods with computational approach. The thermodynamics and reaction pathway of sulfur cathode in MgTFSI₂–DME electrolyte, as well as the associated kinetics are thoroughly investigated. The results here reveal that sulfur undergoes a consecutive staging pathway in which the formation and chain‐shortening of polysulfide occur at early stage accompanied by the dissolution of long‐chain polysulfide, and solid‐state transition from short‐chain polysulfide to magnesium sulfide occurs at late stage. The former process is much faster than the latter due to the synergetic effect of the mediating effect of dissolved polysulfide and the fast diffusion of Mg ion in the amorphous intermediate.     

Rational Design of Statically and Dynamically Stable Lithium–Sulfur Batteries with High Sulfur Loading and Low Electrolyte/Sulfur Ratio

The primary challenge with lithium–sulfur battery research is the design of sulfur cathodes that exhibit high electrochemical efficiency and stability while keeping the sulfur content and loading high and the electrolyte/sulfur ratio low. With a systematic investigation, a novel graphene/cotton‐carbon cathode is presented here that enables sulfur loading and content as high as 46 mg cm^?2 and 70 wt% with an electrolyte/sulfur ratio of as low as only 5. The graphene/cotton‐carbon cathodes deliver peak capacities of 926 and 765 mA h g^?1, respectively, at C/10 and C/5 rates, which translate into high areal, gravimetric, and volumetric capacities of, respectively, 43 and 35 mA h cm^?2, 648 and 536 mA h g^?1, and 1067 and 881 mA h cm^?3 with a stable cyclability. They also exhibit superior cell‐storage capability with 95% capacity‐retention, a low self‐discharge constant of just 0.0012 per day, and stable poststorage cyclability after storing over a long period of six months. This work demonstrates a viable approach to develop lithium–sulfur batteries with practical energy densities exceeding that of lithium‐ion batteries.     

Polyethylenimine Expanded Graphite Oxide Enables High Sulfur Loading and Long‐Term Stability of Lithium–Sulfur Batteries

To realize practical lithium–sulfur batteries (LSBs) with long cycling life, designing cathode hosts with a high specific surface area (SSA) is recognized as an efficient way to trap the soluble polysulfides. However, it is also blamed for diminishing the volumetric energy density and being susceptible to side reactions. Herein, polyethylenimine intercalated graphite oxide (PEI‐GO) with a low SSA of 4.6 m² g^?1 and enlarged interlayer spacing of 13 Å is proposed as a superior sulfur host, which enables homogeneous distribution of high sulfur content (73%) and facilitates Li⁺ transfer in thick sulfur electrode. LSBs with a moderate sulfur loading (3.4 mg S cm^?2) achieve an initial capacity of 1157 and 668 mAh g^?1 after 500 cycles at 0.5 C. Even when the sulfur loading is increased to 7.3 mg cm^?2, the electrode still delivers a high areal capacity of 4.7 mAh cm^?2 (641 mAh g^?1) after 200 cycles at 0.2 C. The excellent electrochemical properties of PEI‐GO are mainly attributed to the homogeneous distribution of sulfur in PEI‐GO and the strong chemical interactions between polysulfides and amine groups, which can mitigate the loss of active phases and contribute to the better cycling stability.     

Sulfur-Induced Low Crystallization of Ultrathin Pd Nanosheet Arrays for Sulfur Ion Degradation-Assisted Energy-Efficient H2 Production

The utilization of thermodynamically favorable sulfur oxidation reaction (SOR) as an alternative to sluggish oxygen evolution reaction is a promising technology for low-energy H₂ production while degrading the sulfur source from wastewater. Herein, amorphous/crystalline S-doped Pd nanosheet arrays on nickel foam (a/c S-Pd NSA/NF) is prepared by S-doping crystalline Pd NSA/NF.  Owing to the ultrathin amorphous nanosheet structure and the incorporation of S atoms, the a/c S-Pd NSA/NF provides a large number of active sitesand the optimized electronic structure, while exhibiting outstanding electrocatalytic activity in hydrogen evolution reaction (HER) and SOR. Therefore, the coupling system consisting of SOR-assisted HER can reach a current density of 100 mA cm⁻² at 0.642 V lower than conventional electrolytic water by 1.257 V, greatly reducing energy consumption. In addition, a/c S-Pd NSA/NF can generate H₂ over a long period of time while degrading S²⁻ in water to the value-added sulfur powder, thus further reducing the cost of H₂ production. This work proposes an attractive strategy for the construction of an advanced electrocatalyst for H₂ production and utilization of toxic sulfide wastewater by combining S-doping induced partial amorphization and ultrathin metal nanosheet arrays.     

Solid-State Electrolytes in Lithium–Sulfur Batteries: Latest Progresses and Prospects

Solid-state lithium–sulfur batteries (SSLSBs) have attracted tremendous research interest due to their large theoretical energy density and high safety, which are highly important indicators for the development of next-generation energy storage devices. Particularly, safety and “shuttle effect” issues originating from volatile and flammable liquid organic electrolytes can be fully mitigated by switching to a solid-state configuration. However, their road to thecommercial application is still plagued with numerous challenges, most notably the intrinsic electrochemical instability of solid-state electrolytes (SSEs) materials and their interfacial compatibility with electrodes and electrolytes. In this review, a critical discussion on the key issues and problems of different types of SSEs as well as the corresponding optimization strategies are first highlighted. Then, the state-of-the-art preparation methods and properties of different kinds of SSE materials, and their manufacture, characterization and performance in SSLSBs are summarized in detail. Finally, a scientific outlook for the future development of SSEs and the avenue to commercial application of SSLSBs is also proposed.     

某大型硫磺制酸装置设计

根据大型硫磺制酸装置的工艺设计要求，就某大型硫磺制酸装置的具体设计，介绍了其工艺流程选择及主要设备选型。事实证明大型硫磺制酸装置采用“3 1”两次转化，三塔两槽两次吸收制酸工艺，技术是先进、可靠的，工艺选择及设备选型是成功的。     

Multiple reactor testing of a synthetic sorbent for regenerative sulfur capture in fluidized bed combustion of coal

A new synthetic regenerable sorbent was developed as an alternative to limestone and dolomite for regenerative sulfur capture in fluidized bed combustion (FBC of coal. The sorbent consists of CaO (8-9 wt%) on a spherical 3 mm diameter γ-Al₂O₃ support. A shrinking unreacted core model (SURE2) is proposed to describe the sulfation process. Experiments have been carried out in a 12 mm internal diameter fixed bed reactor, a 0.05 m ID fluidized bed reactor and a thermobalance. The results obtained for all three reactors are in good agreement with the predictions of the SURE2 model.     

粉尘对铁钙基脱硫剂再生过程的影响

在固定床装置上考察粉尘对铁钙基脱硫剂再生过程的影响 .结果表明 ,在含氧气气氛再生时 ,随着温度的升高 ,粉尘对再生负面的影响越来越显著 ,但是对二次脱硫活性的影响很小 ,这可能与脱硫过程为内扩散控制有关 ;而在含水蒸气气氛中再生时 ,再生率与含氧气气氛再生时相比低得多 ,粉尘对再生的影响与粉尘含量有关 .     

用R_3N·SO_3为磺化剂合成甜蜜素的新工艺研究

在研究了Ｒ３Ｎ·ＳＯ３与环己胺的磺化反应条件的基础上，提出了合成甜蜜素的最佳工艺条件，其合成总收率在９５％左右     

湿法脱硫再生工艺探析

湿法脱硫工艺中,脱硫液中含有大量悬浮硫和杂质盐类,这些物质的存在影响了脱硫的正常运行,采用适当的工艺过程除去悬浮硫和相关盐类,使脱硫液保持较高的吸收能力。