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...

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A low-resistance polypyrrole (PPy) film that can achieve high rates (rates of >1C) while suppressing polysulfide dissolution is developed in this study. To achieve high-rate characteristic in a sulfur cathode with high sulfur loading, a three-dimensional (3D) aluminum foam current collector is used and the Li+ concentration of the PPy film is enhanced by a glyme–Li equimolar complex as the polymerization electrolyte. A PPy–sulfur/ketjenblack (S/KB) 3D aluminum foam laminated cell with a sulfur loading of 5 mg cm−2 is prepared. Consequently, a high discharge capacity of 794 mAh g−1-sulfur at 3.0C is achieved using 1 M lithium bis-(trifluoromethylsulfonyl)imide (LiTFSI) with dimethoxyethane (DME) and 1,3-dioxolane (DOL), (DME/DOL = 1/1 vol.) as the electrolyte and Li foil as the anode. In the cycling test, PPy-S/KB 3D Al foam cathode achieved a significant improvement in discharge capacity retention compared to bare S/KB 3D Al foam cathode without PPy coating. Moreover, almost no polysulfide dissolution is confirmed from the ultraviolet–visible spectrum of the electrolyte after the cycle evaluation. Here, we prepare a 3D structure S/KB cathode that can support high rates while suppressing sulfur dissolution by PPy coating, and reveal its potential for lithium–sulfur battery application.

An anionic polymer coating produced by ultraviolet curing and thermosetting to suppress polysulfide dissolution of the sulfur cathode for lithium-sulfur batteries was investigated. An sulfur/Ketjenblack cathode with a high sulfur loading of 10 mg cm−2 was prepared using a three-dimensional foam current collector. From the current rate and cycle characteristics, the cross-linked polymer coating suppressed the polysulfide dissolution, and the discharge capacities were 1031 and 414 mAh g−1-sulfur at 0.1 and 1.0C, respectively. In a long-term cycle test of 300 cycles, a capacity retention rate was 41%. An average coulombic efficiency was 91% throughout the cycles.

The dissolution of lithium polysulfide (Li2Sx, 4 ≤ x ≤ 8, LiPS) during charge/discharge testing is a critical issue hindering the practical application of lithium-sulfur batteries (LSBs). To suppress LiPS dissolution, we propose a facile method to fabricate a Li-ion-conductive polymer layer by photopolymerization. The electrochemical performance of LSBs was investigated by preparing small pouch cells containing a three-dimensional (3D) structured sulfur-based cathode that either was or was not layered with the new polymer. Analysis of the electrolyte in the LSB pouch cell by UV-Vis spectroscopy revealed that a 3D S cathode with polymer layer shows a good discharge capacity of 535 mA h g-1 and a coulombic efficiency (CE) of over 96% after 40 cycles. In comparison, the 3D S cathode without a polymer layer has a poor discharge capacity of 389 mA h g-1 and a CE of over 22% after 40 cycles. The dissolution suppressing ability of our new polymer layer demonstrates promise for the practical application of LSBs.