Rational Design of Low Cost and High Energy Lithium Batteries through Tailored Fluorine‐free Electrolyte and Nanostructured S/C Composite

Abstract

We report a new Li-S cell concept based on an optimized F-free catholyte solution and a high loading nanostructured C/S composite cathode. The Li S present in the electrolyte ensures both buffering against active material dissolution and Li conduction. The high S loading is obtained by confining elemental S (≈80 %) in the pores of a highly ordered mesopores carbon (CMK3). With this concept we demonstrate stabilization of a high energy density and excellent cycling performance over 500 cycles. This Li-S cell has a specific capacity that reaches over 1000 mA h g , with an overall S loading of 3.6 mg cm and low electrolyte volume (i.e., 10 μL cm ), resulting in a practical energy density of 365 Wh kg . The Li-S system proposed thus meets the requirements for large scale energy storage systems and is expected to be environmentally friendly and have lower cost compared with the commercial Li-ion battery thanks to the removal of both Co and F from the overall formulation.

Designing a Safe Electrolyte Enabling Long‐Life Li/S Batteries

“…Galvanostatic cycling tests were performed to evaluate the effect of Py 1,4 TFSI as an additive on the Li/S cell cycling stability. The cells were built by using an optimized and high‐loading C/S composite cathode, in which the amount of S was maximized to a value up to 80 % and a loading of 4 mg cm −2 . In this way, the influence of the IL additive on the cycling performance of practical high‐sulfur‐loading electrodes can be demonstrated.…”

“…An aqueous solution was prepared by dissolving sucrose (3.14 g) and H 2 SO 4 (0.35 g) in deionized H 2 O (12.55 mL); SBA‐15 (2.51 g) was impregnated with this solution. The mixture was sonicated for 1 h and then heated at 100 °C for 12 h and at 160 °C for 12 h. The silica sample containing partially polymerized and carbonized sucrose was treated again with aqueous solution (12.55 mL) containing sucrose (2 g) and H 2 SO 4 (0.23 g) at 100 and 160 °C, as previously reported . The composite was then heated at 900 °C for 5 h with a heating rate of 5 °C min −1 under nitrogen flow (20 mL min −1 ).…”

“…The as‐prepared mesoporous CMK3 carbon was mixed with sulfur (15:85, w / w ) by high‐energy ball milling at 25 Hz frequency, sealed in a 50 mL vessel under N 2 flow (20 mL min −1 ), and heated at 155 °C for 20 h and at 300 °C for 20 h. The final sulfur content in the CMK3 composite was 80 % …”

Multiple Covalent Triazine Frameworks with Strong Polysulfide Chemisorption for Enhanced Lithium‐Sulfur Batteries

“…To overcome above hurdles, various carbon materials including porous carbon particles,, carbon nanotubes,, carbon nanofibers and graphene, as the sulfur host have been widely exploited, due to their high surface area and excellent electronic conductivity. However, because of weak physical limitation of carbon materials on sulfur, the dissolution of polysulfide and the instability of long cycle remain unsolved ,.…”

“…The insulating nature of both sulfur and its discharge polysulfide products, volume expansion, shuttling effect as well as the Limetal corrosion work in concert to their poor performance such as low active sulfur utilization, coulombic efficiency and cycle stability. [9][10][11][12] To overcome above hurdles, various carbon materials including porous carbon particles, [13,14] carbon nanotubes, [15,16] carbon nanofibers [17][18][19] and graphene [20,21] as the sulfur host have been widely exploited, due to their high surface area and excellent electronic conductivity. However, because of weak physical limitation of carbon materials on sulfur, the dissolution of polysulfide and the instability of long cycle remain unsolved.…”