Two-dimensional boron nitride as a sulfur fixer for high performance rechargeable aluminum-sulfur batteries

Abstract

Aluminum-ion batteries (AIBs) are regarded as promising candidates for post-lithium-ion batteries due to their lack of flammability and electrochemical performance comparable to other metal-ion batteries. The lack of suitable cathode materials, however, has hindered the development of high-performing AIBs. Sulfur is a cost-efficient material, having distinguished electrochemical properties, and is considered an attractive cathode material for AIBs. Several pioneering reports have shown that aluminum-sulfur batteries (ASBs) exhibit superior electrochemical capacity over other cathode materials for AIBs. However, a rapid decay in the capacity is a huge barrier for their practical applications. Here, we have demonstrated systematically for the first time that the two-dimensional layered materials (e.g. MoS2, WS2, and BN) can serve as fixers of S and sulfide compounds during repeated charge/discharge processes; BN/S/C displays the highest capacity of 532 mAh g−1 (at a current density of 100 mA g−1) compared with the current state-of-the-art cathode material for AIBs. Further, we could improve the life-span of ASBs to an unprecedented 300 cycles with a high Coulombic efficiency of 94.3%; discharge plateaus at ~1.15 V vs. AlCl4−/Al was clearly observed during repeated charge/discharge cycling. We believe that this work opens up a new method for achieving high-performing ASBs.

Capacity Retention Analysis in Aluminum-Sulfur Batteries

“…Of note, a similar phenomenon was previously reported for Li-S battery systems. , In such cases, the capacity loss was generally attributed to the dissolution of the polysulfides (i.e., shuttle effect) or S into the electrolyte and to the irreversible formation of insoluble and insulating precipitates. This line of thought was analogously transferred to the field of Al-S batteries, resulting in works that try to improve the electrochemical performance by limiting polysulfide shuttling . In Al-S batteries with the AlCl 3 :[EMIm]­Cl electrolyte, the case appears to be slightly different, considering that S has very low solubility in this ionic liquid.…”

“…Then, a S cathode (integrating an activated carbon cloth that acted as the conductive matrix) was used in conjunction with an electrolyte of AlCl 3 dissolved in 1-ethyl-3-methylimidazolium chloride ([EMIm]­Cl). Interestingly, in the past 4 years, there were only few other reports describing the use of carbon–sulfur composite cathodes with the nonaqueous AlCl 3 :[EMIM]Cl electrolyte. ,− These studies generally make reference to a synergy between the carbon materials and sulfur, which improves the electrochemical performance of Al battery cathodes. Judging from the literature on the state of the art (Figure S1), it appears that this synergetic benefit applies solely to the initial cycles because the capacity decays rapidly.…”

Ionic Liquid-Based Electrolytes for Aluminum/Magnesium/Sodium-Ion Batteries

“…for AIBs. Various materials are performed to realize practical aluminum storage systems based on ionic liquid electrolyte such as carbon materials [47][48][49][50][51][52][53][54][55][56][57][58][59][60][61][62], oxide (transition metal oxide) [63][64][65][66][67][68], transition metal sulfides [69][70][71][72][73][74][75][76], selenides [77][78][79], conducting polymers [80], Prussian blue analogs [81][82][83], and sulfur [39,[84][85][86][87]. The reaction mechanisms of electron transfer with different types in AIBs based on an ionic liquid-based electrolyte are discussed below.…”

Binder-free S@Ti3C2Tx sandwich structure film as a high-capacity cathode for a stable aluminum-sulfur battery

“…The rechargeable Al-S battery was confirmed by Wang's group in 2016; with the help of an activated carbon cloth host, the sulfur cathode completed a short cycle life of 20 cycles [14]. Since then, various sulfur host materials, such as multi-walled carbon nanotube/S cathode [16], carbonized metal-organic frameworks (MOF) [17], boron nitride [18], and reduced graphene oxide + CoS 2 + S composite [19], have been designed. Studies have promoted the development of Al-S batteries, but the cycle stability and reversibility of Al-S batteries still need to be improved.…”