Weakening Li⁺De‐solvation Barrier for Cryogenic Li–S Pouch Cells

Abstract

Li–S batteries hold promise for pushing cell‐level energy densities beyond 300 Wh kg‐1 while operating at low temperatures (LTs, below 0 °C). However, the capacity release of existing Li–S batteries at LTs is still barely satisfactory, and there is almost no verification of the practicability of Li–S batteries at LTs in the Ah‐level pouch cell. Here, antecedent molecular dynamics (MDs) combined with density functional theory analysis are used to systematically investigate Li+ solvation structure in conventional Li–S batteries at LTs, which unprecedentedly reveals the positive correlation between lithium salt concentration and Li+ de‐solvation barrier, indicating dilute electrolytes can enhance the Li+ de‐solvation kinetics and thus improve the capacity performance of cryogenic Li–S batteries. These insights derived from theoretical simulations invested Li–S batteries with a 67.34% capacity retention at −40 °C compared to their room temperature performance. In particular, an Ah‐level Li–S pouch cell using dilute electrolytes with a high sulfur loading (5.6 mg cm‐2) and lean electrolyte condition is fabricated, which delivers a discharge capacity of about 1000 mAh g‐1 and ultra‐high energy density of 350 Wh kg‐1 at 0 °C, offering a promising route toward a practical high‐energy cryogenic Li–S battery.

Excluding the Trouble from Interfacial Water by Covalent Organic Polymer to Realize Extremely Reversible Zn Anode

“…Many literatures have proposed that the de-solvation barriers of solvated ions at the interface of the electrode/electrolyte under low temperature is the main obstacle for achieving good low-temperature performance. [49][50][51] Therefore, it can be deduced that excellent electrochemical performance of COP/Cu@Zn anode at low temperature is due to desolvation of Zn ion under the help of COP layer. In a word, effect of COP layer in realizing de-solvation of Zn ion and regulating Zn deposit ensures high reversibility of COP/Cu@Zn anode.…”

Mechanistic insights into trisulfur radical generation in lithium–sulfur batteries

“…Specically, solvent molecules explicitly bond with solutes, and the (de)solvation energy would be distinct when solutes are coordinated by different numbers of solvents, namely in different solvation statuses (e.g., non-solvated, partially solvated, and fully solvated). [35][36][37] Lin et al found that varying the concentration of electrolytes results in different solvation statuses of poly-suldes, thus signicantly affecting the open circuit voltage of batteries. 38 Whether the solvation statuses of sulfur species affect the generation of trisulfur radicals is worthy of in-depth exploration.…”

“…, non-solvated, partially solvated, and fully solvated). 35–37 Lin et al found that varying the concentration of electrolytes results in different solvation statuses of polysulfides, thus significantly affecting the open circuit voltage of batteries. 38 Whether the solvation statuses of sulfur species affect the generation of trisulfur radicals is worthy of in-depth exploration.…”

A Separator with Double Coatings of Li4Ti5O12and Conductive Carbon for Li‐S Battery of Good Electrochemical Performance

“…In addition, the advantages of sulfur, which has low cost, is easily available, and environmentally friendly, have also attracted wide attentions. [5][6][7][8] However, The 'shuttle effect' and lithium anode corrosion have always restricted the development of Li-S batteries. During the charging and discharging process, the soluble lithium polysulfides (Li 2 S x , 2 < x ≤ 8) are formed and dissolved in the electrolyte, resulting in the loss of active sulfur and corrosion of lithium anodes, which leads to the sharp capacity decline and poor safety performance.…”