High Active Magnesium Trifluoromethanesulfonate-Based Electrolytes for Magnesium–Sulfur Batteries

abundant metal on earth. [19] In view of these merits and the high abundance of sulfur, increasing interest has been raised on post Li-S battery systems, including magnesium-selenium batteries, Mg-S batteries, which display higher energy density, low costs and improved safety in comparison to Li-S batteries. [11,[20][21][22][23] Despite the advantages of Mg-S batteries, major issues in this field are related to the severe overcharge behavior and low sulfur utilization of the cathode during charging and discharging in general, the formation of magnesium polysulfides and the slow diffusion of Mg 2+ , which all result in poor electrochemical behavior. [17,22,24,25] Substantial efforts have been made to improve cell performance so far, including the modification of cathode materials, anodes and separators, [25] the synthesis of novel electrolyte systems, [24,26] which all to some extent can improve the cell behavior. Figure 1d gives a timeline of all the novel findings in the area of Mg-S batteries in each year. Figure 1b demonstrates an overview of the topics addressed in the published research articles in Mg-S batteries. According to this survey, the research community developed a strong preference for investigating novel electrolyte systems, modifying sulfur cathode materials and carrying out mechanistic studies. By contrast, only few research groups devoted their work to the other components of a Mg-S battery, such as the anode and the separator. Major improvements related to the latter two will also be thoroughly discussed in the following sections.Several reviews already discussed the developments in Mg batteries based on intercalation cathode materials. [1,15,[27][28][29][30] By contrast, accounts on Mg batteries containing a sulfur-based conversion cathode, which benefits from high theoretical energy density, a reasonable potential difference with Mg, nontoxicity and high earth abundance [11,31,32] are rare. This review solely refers to Mg-S batteries that use sulfur-based conversion cathodes.The purposes of this review are to summarize and highlight the most up-to-date and novel findings for Mg-S batteries, addressing sulfur-based conversion cathodes and Mg anode materials, separator modifications as well as various electrolyte systems. Furthermore, since the research on Mg-S batteries is still at an initial stage, some challenges, including the capacity decay mechanism, a lack of suitable electrolyte systems and the passivation of the Mg anode, which so far impedes any superior electrochemical performance in Mg-S batteries, will also be addressed. In addition, we also listed and discussed some possible future prospects for high energy Mg-S batteries. Finally, the currently reported Mg-S systems have been summarized in a table for easy comparison.This review on rechargeable Mg-S batteries is arranged in the following sequences. In the first section, currently applied anode materials (various forms of Mg anodes) and prospective anodes are discussed. Next, various sulfur-based conversion cathodes, which mainly...

Section: Anode Materialsmentioning

confidence: 99%

Section: Cathode Materialsmentioning

confidence: 99%

Section: Cathode Materialsmentioning

confidence: 99%

Section: Electrolyte Systemsmentioning

confidence: 99%

Section: Electrolyte Systemsmentioning

confidence: 99%

See 3 more Smart Citations

Rechargeable Magnesium–Sulfur Battery Technology: State of the Art and Key Challenges

Wang

Buchmeiser

2019

A Progress Report on Metal–Sulfur Batteries

Manthiram

2020

106

Nonaqueous conversion-reaction sulfur chemistry has been attracting increasing attention over the past decade for the development of nextgeneration lithium-based batteries. Li-S batteries are currently approaching a nexus stage from lab-scale experiments to possible pragmatic applications. Inspired by the success of Li-S chemistry, other metal-sulfur batteries with a variety of metallic anodes, such as sodium, potassium, magnesium, calcium, and aluminum, have also started to attract attention. In comparison to lithium, Na, Mg, Al, K, and Ca are naturally more abundant and affordable.

Asymmetric SO₃CF₃⁻‐Grafted Boron‐Center Anion Enables Boron‐Containing Interphase for High‐Performance Rechargeable Mg Batteries

Huang,

Tan,

Chen

et al. 2024

Mg(SO3CF3)2 (Mg(OTf)2) is a simple and cost‐effective magnesium salt, which can promote the future applications of rechargeable magnesium batteries (RMBs). However, the simple Mg(OTf)2/ether electrolytes suffer from poor electrochemical properties due to the low solubility of Mg(OTf)2 and the serious decomposition passivation of the [Mg2+‐OTf−] ion pair on Mg. Herein, the OTf− anion is successfully grafted on low‐cost fluoride boronic esters (B(OCxHyF2x‐y+1)3) to obtain the asymmetric and weak‐coordination boron‐center [B(OCxHyF2x‐y+1)3OTf]− anion in ether electrolytes. The ‐OCH2CF3 (TFE) groups in B(TFE)3 effectively realize the charge delocalization of the OTf− and B‐O plane, restraining the independent decomposition of the [Mg2+‐OTf−] ion pair. The co‐decomposition of the asymmetric [B(TFE)3OTf]− induces the formation of the B‐containing organic/inorganic interphase, thus achieving a reversible Mg plating/stripping. After the further solubilization reaction, the obtained electrolyte exhibits a high average coulombic efficiency of 98.13% and long‐term cycling stability (1000 h). Notably, the long cycling life (capacity retention of 90.2% after 600 cycles at 1 C) and high‐rate capacity (43.0 mAh g−1 at 5 C) of the Mg/Mo6S8 full cell demonstrate a favorable electrolyte/cathode compatibility. This work brings new insights to design the new‐type and low‐cost Mg‐salts and high‐performance electrolytes for commercial RMBs.