Nanonet-structured poly(m-phenylene isophthalamide)–polyurethane membranes with enhanced thermostability and wettability for high power lithium ion batteries

Abstract

To solve the thermal shrinkage, flammability and wettability problems of conventional polyolefin separators, we have prepared the nanonet-structured poly(m-phenylene isophthalamide)-polyurethane (PMIA-PU) nanofibrous membranes with enhanced thermostability and good wettability for high power lithium ion batteries (LIBs) via a one-step electrospinning technique. The as-prepared PMIA-PU membranes demonstrate improved mechanical strength (>15.79 MPa) and high ionic conductivity up to 1.38 mS cm À1 due to the introduction of PU and the formation of the nanonet structure. Benefiting from the introduction of PMIA, the as-prepared PMIA-PU membranes were endowed with not only improved thermostability and non-flammability but also excellent wettability to liquid electrolytes, which could be beneficial for improving the safety and reliability of LIBs. Moreover, the excellent affinity between the carboxy group (PMIA and PU) and the carbonate ester group of the liquid electrolyte endows the PMIA-PU membranes with good anodic stability up to 4.86 V. More importantly, the PMIA-PU membrane based Li/LiFePO 4 cell exhibits comparable cycling stability, delivering a discharge capacity of 160 mA h g À1 at the 65th cycle and better rate capability compared with the Celgard membrane based cell. These results indicate a very promising direction for safe and reliable separators, which may make further progress in obtaining the enhanced performance of LIBs.

Study on the structural design and performance of novel braid-reinforced and thermostable poly(m-phenylene isophthalamide) hollow fiber membranes

“…[26][27][28][29][30][31] The chemical structure formula and thermodynamics performance of PMIA are shown in Fig. 1, S1 and S2.…”

Poly(aryl ether ketone) composite membrane as a high‐performance lithium‐ion batteries separator

“…The performance of the assembled cell was investigated by charged‐discharged measurements. Figure (a) shows the initial charge–discharge curves with voltage ranging from 2.50 to 3.85 V at a rate of 0.5 C. A pair of well‐defined plateaus near 3.36 and 3.50 V is the characteristic biphasic Li + extraction and insertion feature of LiFePO 4 cathode . The charge and discharge capacity of the assembled cell is 150.2 and 141.6 mAh g −1 at the first cycle, respectively.…”

“…Nanonet‐structured poly(m‐phenylene isophthalamide)‐polyurethane nanofibrous membranes were prepared via one‐step electrospinning technique. The electrolyte wettability and anodic stability was greatly enhanced due to the harmonious affinity between the electrolyte and poly(m‐phenyleneisophthalamide)‐polyurethane . For better expansion of the practical applicability, separators with low thermal shrinkage and outstanding liquid electrolyte wettability need to be further explored.…”

Effect of polyhydric alcohols on the mechanical and thermal properties, porosities, and air permeabilities of polyurethane‐blended films

“…1,3 Due to its ability to form excellent membranes and separators, PU can also be used in coatings for flexile substrates, such as breathable textiles, edible packaging films, rubber, and car interiors. 5,6 Waterborne polyurethane (WBPU), which exhibits lower toxicity and is flexible, 1-4 is attracting more attention than PU from environmental and mechanical perspectives. However, the mechanical properties, such as the adhesion and tensile strength of PU, are superior to those of WBPU, which has led to PU mainly being used in industry.…”