Recent Progress and Emerging Application Areas for Lithium–Sulfur Battery Technology

Abstract

With the ever-increasing need for electrification across many application sectors, the development of new energy-storage technologies is of increasing relevance and critical importance. Electrification is progressing significantly within the traditional transportation sectors such as electric bikes, cars, buses, and other commercial vehicles, enabled by continued cell development and Gigafactory-scale mass production of Li-ion battery (LIB) technology. However, two key factors are starting to drive the need for new solutions to be found. One factor is the secure supply of key elements-mainly cobalt and nickelused in most of the conventional Li-ion cells which are becoming increasingly critical. The other is the performance requirements of desirable emerging application areas that are beyond the capabilities of traditional LIB technology. Examples include large commercial vehicles, [1] high-altitude long endurance (HALE), high-altitude pseudosatellites (HAPS), electric vertical takeoff and landing (eVTOL), [2] and electric passenger aircraft. The weight of the battery system (BSM) is an especially critical factor for these aviation applications. The battery systems' performance requirements differ across these applications: power, cycle life, system cost, etc. However, the need for a high gravimetric energy density, 400 Wh kg À1 and beyond, is common across them all. Higher energy battery systems will enable these vehicles to achieve extended range, a longer mission duration, lighter vehicle weight, or increased payload. In the following sections, key advantages, limitations, and progress made to extend cycle life, energy, power, and safety of Li-S battery management systems (BMS) are described. Further, recent advances regarding modeling, battery system management, and the integration of Li-S batteries into present as well as future real-world applications are summarized. 2. Lithium-Sulfur Battery Technology 2.1. Advantages LIB systems are the current technology of choice for many applications; however, the achievable specific energy reaches a maximum at around 240-300 Wh kg À1 at the cell level. [3] Emerging

Sulfur Transfer Melt Infiltration for High‐Power Carbon Nanotube Sheets in Lithium‐Sulfur Pouch Cells

“…This calculation include 40 double‐sided CNT BP cathodes, thin lithium metal anodes (50 μm), and weight savings of inactive material by varying perforation concepts for the free‐standing CNT cathodes. Depending on the application and its energy and power requirements, thin‐film cathodes with lower sulfur loadings than 1.5 mg S cm −2 are ideal candidates for cycling at higher C‐rates in combination with mass reduction due to the perforation leading to specific energy densities of 300 Wh kg −1 [11] . Otherwise, high capacity cathode systems with sulfur loadings >2.0 mg S cm −2 for free‐standing electrode concepts achieve gravimetric energy densities up to >400 Wh kg −1 [59] …”

“…So far, only few values of power density or specific energies at C‐rates >0.1 C have been reported for Li−S prototype cells. Oxis Energy recently published 300 Wh kg −1 with maximum C‐rate of 3 C and the Dalian University reported a pouch cell with 350 Wh kg −1 and 60 W kg −1 , that was cycled 30 times with 0.2 C [11,12] …”

Electrolyte Structure of Lithium Polysulfides with Anti‐Reductive Solvent Shells for Practical Lithium–Sulfur Batteries

“…Furthermore,s paringly solvating electrolytes suppress the parasitic reactions at the significant cost of kinetic performance of Sc athode,w hich is unfavorable in practical batteries. [25,33] Therefore,t he fundamental understanding and rational regulation of electrolyte structures of PSs is strongly required to understand and inhibit the parasitic reactions between PSs and Li metal.…”

Impact of Carbon Porosity on Sulfur Conversion in Li−S Battery Cathodes in a Sparingly Polysulfide Solvating Electrolyte

“…Additionally, the volumetric energy density on cell level is another bottleneck of this battery technology due to the intrinsic low mass density of the utilized elements (sulfur and carbon). Sparingly polysulfide solvation electrolytes have the potential to overcome this issue as they enable the work under lean conditions [13] …”

“…Sparingly polysulfide solvation electrolytes have the potential to overcome this issue as they enable the work under lean conditions. [13] Mostly, studies deal with the current state-of-the-art ether-based electrolyte, comprising 1 M lithium bis(trifluoromethane-sulfonyl)imide (LiTFSI) conductive salt dissolved in 1,2-dimethoxyethane (DME) and 1,3-dioxolane (DOL) in equal volumetric ratio. [4,6,14] This electrolyte results in a catholyte-type battery system with high LiPS solubility and thus, active material is almost completely dissolved.…”