Constructing interlayers with micro-nano particles to enhance the fire safety and polysulfide adsorption ability of polypropylene separators for lithium-sulfur batteries
writer：Tao Zhu, Shuheng Wang, Jiasu Li, Dongli Chen, Xiaoyu Gu, Jun Sun, Bin Xu, Sheng Zhang
keywords：Flame-retardancy，Micro-nano particles，Chemical adsorption，Interlayer，Lithium-sulfur battery
source：期刊
Issue time：2022年
Lithium-sulfur batteries (LSBs) are widely accepted representatives of next-generation energy storage with high energy density. However, the high flammability of polypropylene (PP) separators and ether electrolytes deteriorates the safety of LSBs. Moreover, the severe shuttle effect of lithium polysulfides (LiPSs) induces the capacity degradation and poor cycle stability of LSBs. In this work, we unprecedentedly synthesize multifunctional micro-nano-sized particles (ACNP) that are constructed on PP separators to improve the safety and electrochemical performance of LSBs. The ACNP is obtained by the electrostatic assembly of ammonium polyphosphate and chitosan. The presence of ACNP decreases the burning process and improves the thermal stability of separators and electrolytes. Besides, the temperature of pouch cells during combustion is decreased after the addition of ACNP or ACNP@super-P(SP) interlayers. Moreover, the abundant N-containing and O-containing groups in the ACNP layer effectively inhibit the shuttle effect of LiPSs via chemical adsorption, increase the affinity to electrolytes, and facilitate the Li+ diffusion and redox kinetics. The SP enhances the conductivity of the interlayer, thus enhancing the capacity and cycle stability of LSBs. It is expected that this work provides a universal strategy to enhance the safety of separators as well as the batteries.
鋰硫電池（LSB）是被廣泛接受的具有高能量密度的下一代儲(chǔ)能代表。然而，聚丙烯（PP）隔膜和乙醚電解質(zhì)的高可燃性使LSB的安全性惡化。此外，多硫化鋰（LiPSs）的嚴(yán)重穿梭效應(yīng)誘發(fā)了LSB的容量下降和循環(huán)穩(wěn)定性差。在這項(xiàng)工作中，我們史無(wú)前例地合成了多功能微納大小的顆粒（ACNP），這些顆粒被構(gòu)建在PP分離器上，以改善LSB的安全性和電化學(xué)性能。ACNP是由聚磷酸銨和殼聚糖的靜電組裝得到的。ACNP的存在減少了燃燒過(guò)程，提高了分離器和電解質(zhì)的熱穩(wěn)定性。此外，加入ACNP或ACNP@super-P(SP)夾層后，燃燒過(guò)程中袋式電池的溫度下降。此外，ACNP層中豐富的含N和含O基團(tuán)通過(guò)化學(xué)吸附有效地抑制了LiPSs的穿梭作用，增加了與電解質(zhì)的親和力，促進(jìn)了Li+擴(kuò)散和氧化還原動(dòng)力學(xué)。SP增強(qiáng)了層間的導(dǎo)電性，從而提高了LSB的容量和循環(huán)穩(wěn)定性。預(yù)計(jì)這項(xiàng)工作將提供一個(gè)通用的策略來(lái)提高分離器以及電池的安全性。