Carbon‐to‐sulfur ratio in the cell controls the discharge capacity, cycling performance and energy density of a lithium‐sulfur battery

Abstract

Summary Cell design is a compelling feature to attain lithium‐sulfur (Li‐S) batteries with superior performance and carbon‐to‐sulfur (C/S) ratio is a vital design parameter with a critical influence on the battery performance. Herein, the dependence of the Li‐S battery performance on the C/S ratio is examined for various electrolyte‐to‐sulfur (E/S) ratios based on experimentally measured peak discharge capacities and cycling performance aside from the gravimetric and volumetric energy densities projected by the cell‐ and system‐level performance models. C/S ratio has a great influence on the cycling performance and discharge capacity, particularly for cells with a limited amount of electrolyte. The Li‐S cell having a C/S ratio of 2 and an E/S ratio of 13 μL mg−1 has provided the highest initial capacity in addition to the best capacity retention. Model predictions suggest that increasing C/S ratio worsens the battery metrics at the pack level, particularly at low E/S ratios. Assessment of the performance based on the energy density is highly important; the best battery performance at the system level is calculated for the Li‐S battery with the lowest E/S and C/S ratios despite that a lower discharge capacity has been achieved with this cell.

Atomic V- and Co-Modified Ketjen Black–Sulfur Composite for High-Performance Lithium–Sulfur Batteries

“…Similarly, S loading in the cathode controls the battery performance through discharge capacity, cycling performance, and system-level metrics. Moderate S loadings enhance the discharge capacity and cycle life, while high loadings are essential to improve the battery′s energy density. , Consequently, to reach high performance, all other than the active materials should be minimized in the cell along with maximized specific capacity and cycle life.…”

Electrochemical Impedance Spectroscopy of Li‐S Batteries: Effect of Atomic Vanadium‐ and Cobalt‐Modified Ketjen Black‐Sulfur Cathode, Sulfur Loading, and Electrolyte‐to‐Sulfur Ratio

“…Still, a one‐dimensional concentration‐independent electrochemical model was introduced to describe the current‐voltage relationship in the cell. Moreover, the system‐level performance model was revised to consider experimental inputs, including specific capacity, S : C:binder wt.%, and material properties [39,40,41,42] . Experimentally tested sulfur loadings and E/S ratios were fed into the model by altering electrolyte vol.% and electrode thickness parameters.…”

Influence of Sulfur Loading on Lithium‐Sulfur Battery Performance for Different Cathode Carbon Types

“…Recently, modeling and characterization of the key parameters, such as the electrolyte-to-sulfur (E/S) ratio and the carbon-to-sulfur (C/S) ratio, have been reported in the literature. [3][4][5][6][7][8] Sulfur loading is another essential design parameter in the cathode, which is highly determinative of the LiÀ S performance; the energy density of LiÀ S batteries is expected to excel at high levels of sulfur loadings. [9] On the other hand, low S loadings and high E/S ratios are typically desired for LiÀ S batteries to have high discharge capacities and prolonged cycle life (S loadings < 2 mg cm À 2 and E/S ratios > 35 mL g À 1 are typical in the literature [10][11][12] ).…”