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

Abstract

Lithium-sulfur batteries have great potential to satisfy the increasing demand of energy storage systems for portable devices, electric vehicles, and grid storage because of their extremely high specific capacity, costeffectiveness, and environmental friendliness. In spite of all these merits, the practical utilization of lithium-sulfur batteries is impeded by commonly known challenges, such as low sulfur utilization (<80%), short life (<200 cycles), fast capacity fade, and severe self-discharge effect, which mainly result from the i) low conductivity of the active material, ii) serious polysulfide shuttling, iii) large volume changes, and iv) lithium-metal anode contamination/corrosion. Numerous approaches are reported to effectively mitigate these issues. Indeed, such approaches have shown enhanced lithium-sulfur battery performances. However, many reports overlook the critical parameters, including sulfur loading (<13 mg cm −2 ), sulfur content (<70 wt%), and electrolyte/sulfur ratio (>11 µL mg −1 ), that significantly affect the analyzed electrochemical characteristics, energy density, and practicality of lithium-sulfur batteries. This review highlights the trends and progress in making cells fulfilling these fabrication parameters and discuss the challenges of the amount of sulfur and electrolyte in fabricating cells with practically necessary parameters and with high electrochemical utilization and efficiency.

Rational Design of Binders for Stable Li‐S and Na‐S Batteries

“…The actual discharge products and energy conversion in each step are different between Li-S and Na-S, as shown in Figure 1B,C. [23][24][25] The Na + with a larger ionic radius than Li + can induce a more sluggish reaction. In comparison, although Na-S follows the similar conversion of solid→liquid→solid process, the lower-order intermediates (Na 2 S m , m ≤ 4) is formed at deep discharge (<1.65 V), which induces an increased resistance and prevents the further discharge process to fully release the theoretical capacity of sulfur electrode (1675 mAh g −1 ).…”

A Li2S‐TiS2‐Electrolyte Composite for Stable Li2S‐Based Lithium–Sulfur Batteries

“…[18,19,49,53] Besides enhancing the reaction kinetics, TiS 2 can also immediately adsorb any polysulfides generated from the surrounding Li 2 S, and these stabilized polysulfides can then function as catholyte to benefit the cyclability and high-rate performance of the high-loading cathode. [2,3,[7][8][9] After investigating the obvious morphological differences between the Li 2 S-E and Li 2 S-TiS 2 -E cathodes, we applied different electrochemical analytical tools to explore the activation and cycling performance of the cells (Figure 3). The cycled Li 2 S-E control cathode displays unreacted bulk Li 2 S covered by Adv.…”

“…[1][2][3][4][5] Lithium-sulfur batteries are appealing to fulfill these needs as a result of their high charge-storage capacity and low cost. [1][2][3][4][5] Lithium-sulfur batteries are appealing to fulfill these needs as a result of their high charge-storage capacity and low cost.…”

“…However, nanoparticles are more sensitive to air and moisture and tend to aggregate, [7,[25][26][27] resulting in high resistance. [2,3] A result of these is a low amount of active material in the cathode (e.g., a Li 2 S loading of <2.0 mg cm −2 and Li 2 S content of <60 wt%) and a high amount of electrolyte in the cell (e.g., high electrolyte/Li 2 S ratio of > 20/1). [2,3] A result of these is a low amount of active material in the cathode (e.g., a Li 2 S loading of <2.0 mg cm −2 and Li 2 S content of <60 wt%) and a high amount of electrolyte in the cell (e.g., high electrolyte/Li 2 S ratio of > 20/1).…”

“…[28,29] The degradation of both the anode and the cathode results in a fast capacity fade and short cycle life. [2,3,30] To overcome these challenges, various approaches have been proposed to reduce the overpotential associated with the high activation overpotential of Li 2 S as well as to limit the instability and inefficiency caused by the insulating nature of Li 2 S and the irreversible diffusion of polysulfides. [2,3,30] To overcome these challenges, various approaches have been proposed to reduce the overpotential associated with the high activation overpotential of Li 2 S as well as to limit the instability and inefficiency caused by the insulating nature of Li 2 S and the irreversible diffusion of polysulfides.…”