In-situ growth strategy to construct "four-in-one" separators with functionalized polyphosphazene coatings for safe and stable lithium-sulfur batteries
writer：Xinxin Dong
keywords：battery safety, coating modifed separators, in situ growth, lithium-sulfurbatteries, polyphosphazene
source：期刊
Issue time：2024年
Lithium–sulfur batteries (LSBs) are facing many challenges, such as the inadequate conductivity of sulfur, the shuttle effect caused by lithium polysulfide (LiPSs), lithium dendrites, and the flammability, which have hindered their commercial applications. Herein, a “four-in-one” functionalized coating is fabricated on the surface of polypropylene (PP) separator by using a
novel flame-retardant namely InC-HCTB to meet these challenges. InC-HCTB is obtained by cultivating polyphosphazene on the surface of carbon nanotubes with an in situ growth strategy. First, this unique architecture fosters an enhanced conductive network, bolstering the bidirectional enhancement of both ionic and electronic conductivities. Furthermore, InC-HCTB effectively inhibits the shuttle effect of LiPSs. LSBs exhibit a remarkable capacity of 1170.7 mA h g?1 at 0.2 C, and the capacity degradation is a mere 0.0436% over 800 cycles at 1 C. Third, InC-HCTB coating serves as an ion migration network, hindering the growth of lithium dendrites. More importantly, InC-HCTB exhibits notable flame retardancy. The radical trapping action in the gas phase and the protective effect of the shielded char layer in the condensed phase are simulated and verified. This facile in situ growth strategy constructs a “four-in-one” functional separator coating, rendering InC-HCTB a promising additive for the large-scale production of safe and stable LSBs.
鋰硫電池（LSB）面臨著許多挑戰(zhàn)，例如硫的導(dǎo)電性不足、多硫化鋰（LiPS）引起的穿梭效應(yīng)、鋰枝晶和可燃性等，這些都阻礙了其商業(yè)應(yīng)用。為此，我們利用新型阻燃劑InC-HCTB在聚丙烯（PP）隔膜表面制備了“四合一”功能化涂層來(lái)應(yīng)對(duì)這些挑戰(zhàn)。InC-HCTB是通過(guò)采用原位生長(zhǎng)策略在碳納米管表面培養(yǎng)聚磷腈而獲得的。首先，這種獨(dú)特的架構(gòu)促進(jìn)了增強(qiáng)的導(dǎo)電網(wǎng)絡(luò)，支持離子和電子導(dǎo)電性的雙向增強(qiáng)。此外，InC-HCTB有效抑制 LiPS 的穿梭效應(yīng)。 LSB在0.2 C下表現(xiàn)出1170.7 mA hg-1的卓越容量，并且在1C下800次循環(huán)后容量衰減僅為0.0436%。第三，InC-HCTB涂層充當(dāng)離子遷移網(wǎng)絡(luò)，阻礙了鋰枝晶的生長(zhǎng)。更重要的是，InC-HCTB表現(xiàn)出顯著的阻燃性。模擬驗(yàn)證了氣相中的自由基捕獲作用和凝聚相中屏蔽炭層的保護(hù)作用。這種簡(jiǎn)便的原位生長(zhǎng)策略構(gòu)建了“四合一”功能隔膜涂層，使InC-HCTB成為大規(guī)模生產(chǎn)安全穩(wěn)定LSB的有前景的添加劑。