In situ grown MOFs and PVDF-HFP co-modified aramid gel nanofiber separator for high-safety lithium–sulfur batteries

Jianwei Liu; Jianan Wang; Lei Zhu; Xin Chen; Gong Yi; Qianyue Ma; Shiyi Sun; Ning Wang; Xiangming Cui; Qinqin Chai; Jiangtao Feng; Wei Yan

doi:10.1039/D2TA03301A

In situ grown MOFs and PVDF-HFP co-modified aramid gel nanofiber separator for high-safety lithium–sulfur batteries†

Jianwei Liu,^a Jianan Wang,

*^ab Lei Zhu,^ac Xin Chen,^a Gong Yi,^d Qianyue Ma,^a Shiyi Sun,^a Ning Wang,^e Xiangming Cui,^a Qinqin Chai,^f Jiangtao Feng^a and Wei Yan

*^a

Author affiliations

* Corresponding authors

^a Department of Environmental Science and Engineering, State Key Laboratory of Multiphase Flow in Power Engineering, Xi'an Jiaotong University, 28 Xianning West Road, Xi'an 710049, China

^b Department of Chemical and Process Engineering, Faculty of Engineering and Physical Sciences, University of Surrey, Guildford GU2 7XH, Surrey, England, UK

^c School of Physics and Electrical Engineering, Weinan Normal University, Chaoyang Street, Weinan 714099, China

^d Advanced Technology Institute, University of Surrey, Guildford, Surrey GU2 7XH, England, UK

^e Environmental and Chemical Engineering, Xi'an Polytechnic University, Xi'an, China

^f Xi'an Hantang Analysis & Test Co., Ltd, Xi'an, China

Abstract

Safety-related issues have always been one of the most critical barriers hindering the large-scale popularization of high-energy-density storage systems. For lithium–sulfur (Li–S) batteries, conventional polyolefin separators with poor flash points and weak mechanical strength suffer from potential safety hazards that may cause fire and even explosion under extreme operating conditions. Herein, a thermotolerant poly-m-phenyleneisophthalamide (PMIA)-based gel polymer electrolyte separator (P-PMIA@ZIF-8) was designed by introducing high ion-conductive poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) and in situ-grown zeolitic imidazolate framework-8 (ZIF-8) secondary nanostructures. The P-PMIA@ZIF-8 separator exhibited high-flux Li-ion diffusion and effective “shuttle effect” suppression due to its abundant multilevel pore structure and strong physicochemical anchoring ability toward soluble polysulfides (Li₂S_x) resulting from the ZIF-8 secondary nanostructures. High mechanical properties (tensile strength and puncture force of up to 15 MPa and 0.95 N) and excellent thermal stability (no dimensional change even at an elevated temperature of 200 °C) of the P-PMIA@ZIF-8 separator can further physically block lithium dendrite growth and prevent the occurrence of potential safety accidents. Accordingly, the Li–S batteries with the P-PMIA@ZIF-8 separator delivered a reversible capacity of 855 mA h g⁻¹ after 300 cycles at 0.2C with a slow capacity decay of 0.086% per cycle. Even under the conditions of lean electrolyte (E/S = 5 mL g⁻¹) and low N/P ratio (2.0), the P-PMIA@ZIF-8 separator still exhibited a steady cycling performance with a high gravimetric energy density of 216 W h kg_cell⁻¹, highlighting its bright prospects in future high-energy-density battery systems.

Journal of Materials Chemistry A

In situ grown MOFs and PVDF-HFP co-modified aramid gel nanofiber separator for high-safety lithium–sulfur batteries†

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In situ grown MOFs and PVDF-HFP co-modified aramid gel nanofiber separator for high-safety lithium–sulfur batteries

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