Application of polyamide 6 microfiber non-woven fabrics in the large-scale production of all-solid-state lithium metal batteries

Abstract

All-solid-state electrolytes have received extensive attention due to their excellent safety and good electrochemical performance. However, due to the harsh conditions of the preparation process, the commercial production of all-solid-state electrolytes remains a challenge. The outbreak of the novel coronavirus pneumonia (COVID-19) has caused great inconvenience to people, while also allowing soft, lightweight and mass-producible non-woven fabrics in masks come into sight. Here, a polymer/polymer solid composite electrolyte is obtained by introducing the polyamide 6 (PA6) microfiber non-woven fabric into PEO polymer through the hot-pressing method. The addition of the PA6 non-woven fabric with lithium-philic properties can not only reduce the crystallinity of the polymer, but also provide more functional transmission sites and then promote the migration of lithium ions at the molecular level. Moreover, due to the sufficient mechanical strength and flexibility of the PA6 non-woven fabric, the composite electrolyte shows excellent inhibition ability of lithium dendrite growth and high electrochemical stability. The novel design concept of introducing low-cost and large-scale production of non-woven fabrics into all-solid-state composite electrolytes to develop high-performance lithium metal batteries is attractive, and can also be broadened to the combination of different types of polymers to meet the needs of various batteries.

Solid polymer electrolytes: Ion conduction mechanisms and enhancement strategies

“…In addition, the weak and cross-linked ceramic networks may affect the flexibility of the composite electrolytes. In order to achieve high flexibility of composite polymer electrolyte membranes, a few organic materials like PVDF nanofiber [193], polyamide 6 (PA6) microfiber non-woven fabric [194], cellulose nanofiber (CNF) [195], aramid nanofiber (ANF) [73,196], and polyimide nanofiber [197] are further utilized as 3D nanofiller frameworks. However, the large nanofiller size and the limited contact area and interaction between the non-conductive nanofillers and the polymer matrices may be detrimental to the ionic conductivity.…”

“…As we have mentioned in Section 3.3.3, the porous ceramic electrolytes (e.g., LLZO, LLTO, LAGP, and LATP) with high ionic conductivity have been used as substrates to prepare CPE membranes for high ionic conductivity and mechanical strength; however, the membranes are too brittle and inflexible, and the thickness is usually higher than 100 μm [187-189, 191, 232]. To reduce the thickness and meanwhile increase the flexibility of the electrolyte membranes, organic substrates composed of PVDF nanofiber [193], PA6 microfiber non-woven fabric [194], CNF [195], ANF [73,196], polyimide nanofiber [233,197], and polyethylene separator [242,243] are further utilized to prepared CPEs. Nevertheless, the organic substrate-supported CPE films have much lower ionic conductivity than the ceramic electrolyte substrate-supported CPEs, because of the low intrinsic conductivity and high content of the organic substrates.…”

Research progress in stable interfacial constructions between composite polymer electrolytes and electrodes

“…7a–e). 118 After hot pressing, the combination between polyamide and PEO-LiTFSI was tight and without boundaries, which was good for the electrochemical performance. Subsequently, Guo et al reduced the porosity of LLZTO and polyvinylidene fluoride (PVDF) composite electrolytes by hot pressing, achieving a high ionic conductivity (1.08 × 10 −4 S cm −1 ) at 60 °C (Fig.…”