The Potential for the Creation of a High Areal Capacity Lithium-Sulfur Battery Using a Metal Foam Current Collector

Abstract

A high areal capacity lithium-sulfur battery making use of mass produced aluminum metal foam as a current collector was investigated. A sulfur/Ketjenblack (KB) composite was filled and deposited into the aluminum foam current collector via a predetermined filling procedure, resulting in high sulfur loading. The value for this loading was found to be 17.7 mg sulfur/cm 2 by using carboxymethyl cellulose and styrene butadiene rubber (CMC + SBR) as a binder. An operating single-layer pouch-type cell with an S/KB-CMC+SBR on Al foam cathode was created as a result of this synthesis and found to possess an unprecedentedly high areal capacity of 21.9 mAh/cm 2 . On the basis of the achieved areal capacity, the energy density of a theoretical lithium-sulfur battery was estimated with the assumption of an electrolyte/sulfur ratio of 2.7 μL/mg. This was calculated upon 100% of the pore volume in the S/KB-CMC + SBR on Al foam cathodes and polyolefin separator, along with the inclusion of the weights of the tabs for the current lead and pouch film packaging in the case of a seven-layer pouch-type battery. With this calculation, it was determined that the creation of a lithium-sulfur battery with an energy density of greater than 200 Wh/kg is plausible. Since the commercial launch of the lithium ion battery (LIB) by Sony in 1991, 1 the range of application of this type of battery has been broadened for use in everything from small portable electronic devices to large electric vehicles and stationary batteries capable of storing the power generated by means of solar and wind sources. Such an expansion in the range of applications for LIBs requires them to possess a high energy density, remain safe to use, and to manufactured at a low cost. Considering the requirement for high energy density, there are two general methods by which this can be achieved: increasing the operating voltage or increasing the capacity.Considering the first method, the use of high operating potential cathodes such as spinel (LiNi 0.5 Mn 1.5 O 4 ), 2 olivine-type (LiCoPO 4 3 and LiNiPO 4 4 ), and fluoride phosphate (Li 2 CoPO 4 F) 5 have been investigated. Such cathode materials are promising for use in transportation applications because of both their high operating potential and high volumetric energy density.Considering high capacity cathodes, both sulfur (1675 mAh/g) 6,7 and air cathodes [8][9][10][11] have been investigated. These cathodes possess extremely high capacities with the ability to overcome the shortcoming of their low operating potential, thereby increasing their energy density. Issues arise, however, with the use of the air cathode with a lithium metal anode, which include poor reversibility of the discharged product, the occurrence of a high over-potential during charging and discharging, and the penetration of ambient air into the system resulting in the degradation of lithium metal by moisture.In comparison with the air cathode, the sulfur cathode seems to be a more promising candidate for its use as a high capacity cathode. The su...

Progress on the Critical Parameters for Lithium–Sulfur Batteries to be Practically Viable

“…The increased interest in investigating practical battery conditions has resulted in improved sulfur loading (>10 mg cm −2 ), sulfur content (55–75 wt%), and low electrolyte/sulfur ratios (3–8) in lithium–sulfur cells reported in the last five years. Currently, more studies have demonstrated the intention of enhancing these key parameters in parallel (Table S1, Supporting Information), which we view as a positive trend in the field …”

“…In 2017, Nara et al presented a comprehensive balance in the cathode with a sulfur loading of 17.7 mg cm −2 utilizing an electrolyte/sulfur ratio of just 2.7. These electrolyte/sulfur ratio calculations took into consideration the pore volume in the cathode and separator …”

Effects of Sulfur Loading, Cathode Porosity, and Electrolyte Amount on Li-S Battery Performance with Solvate Ionic Liquid Electrolyte

“…12 Increasing the sulfur loading amount and reducing the electrolyte volume simultaneously is essential for practical applications of the Li-S battery, where an energy density of 300 Wh kg ¹1 is expected. 17 Three-dimensional (3D)-current collectors have been employed for increasing the sulfur loading, [18][19][20][21] but there has been limited success in simultaneously achieving reduction of the electrolyte amount. Furthermore, reducing the amount of conventional ether-based electrolytes that dissolve PS, such as 1 M Li-bis(trifluoromethane sulfonyl)amide (Li[TFSA]) in 1,3-dioxolane/1,2-dimethoxyethane (DOL/DME), leads to degradation of battery performance.…”

An Integrated Strategy towards Enhanced Performance of the Lithium–Sulfur Battery and its Fading Mechanism

“…[37] To solve these issues, various 3D currentc ollectors have been in-vestigated, which allow ah igh sulfur loading, efficient charge transfer and long cycling stability. [37][38][39][40][41][42][43][44] However,t hese innovative structuresh ave some drawbacks, including:a )complex and expensive fabrication procedures that are difficult to scale up, b) as pecial sulfur introductions tep that is incompatible with traditional slurry preparation processes, c) the demand for large electrolyte volumet ow et the electrode, which sacrifices the overall energy density. [35,45] Current collectors that offset these shortfalls while maintaining some structural advantages are desirable.…”