Technological breakthrough: ultra-philic electrolyte lithium battery separator comes out

by:CTECHi     2021-08-07

Lithium Grid News: Lithium-sulfur batteries have attracted great attention from academia and industry because of their high theoretical specific capacity (1675 mAh g-1) and energy density (2600 Wh kg-1). However, serious problems such as polysulfide (Li2Sn, 4 ≤ n ≤ 8) shuttle and poor sulfur conductivity have severely restricted the practical application of lithium-sulfur batteries. At present, researchers have taken many measures to address the above problems, such as sulfur composite electrodes. Recent studies have shown that the separator has an important impact on battery performance, including inhibition of shuttle, dendrite regeneration, interface stability and safety.

Recently, the team of Zhang Junping, a researcher at the Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, reported for the first time a clay mineral super-philic electrolyte lithium battery separator. Laponite is rich in O active sites and Li+, and also has a unique lamella structure and a large specific surface. Laponite was used in lithium-sulfur batteries for the first time to inhibit the shuttle of polysulfides and improve the Li+ conductivity of the separator.

Studies have shown that the clay mineral super-electrolyte membrane has a significant inhibitory effect on the shuttle of polysulfide, and at the same time has high Li+ conductivity, rapid Li+ transfer, super-electrolyte and relatively High thermal stability. When it is applied to lithium-sulfur batteries, it has excellent performance in terms of cycle stability, rate performance, and suppression of self-discharge. Studies on the mechanism of inhibition of polysulfide shuttles show that Li-S bonds and Li˙˙˙O bonds are formed between polysulfides and the O active sites of clay minerals, so that the shuttles of polysulfides can be effectively inhibited. Compared with reports in the literature, the clay mineral super-philic electrolyte lithium battery separator has obvious advantages in lithium-sulfur batteries. In addition, the separator has good universality, can be prepared by a simple coating method, and exhibits excellent performance in both LiFePO4 and lithium-sulfur batteries.

The research work was published in 'Advanced Energy Materials' (Adv Energy Mater 2018, 8, 1801778) and was selected as the front cover. The above work was supported by the 'Hundred Talents Program' of the Chinese Academy of Sciences, the National Natural Science Foundation of China, and the Gansu Basic Research Innovation Group.

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