Interconnected Porous Poly(ether imide) Separator for Thermally Stable Sodium Ion Battery

Abstract

Due to the abundance and low costs of sodium resources, sodium ion batteries have attracted increasing attention for large-scale energy applications. The separator is one of the key materials that determines the performance of sodium ion batteries. Here a separator for sodium ion batteries is prepared using a thermally stable poly­(ether imide) (PEI) and polyvinylpyrrolidone (PVP) blend via immersion phase separation. The PEI/PVP separators show an interconnected porous structure due to the secondary stage demixing of PVP and PEI polymers. The PEI/PVP separator demonstrated better wettability, higher ionic conductivity (1.14 mS cm–1), and higher thermal stability (up to 180 °C) compared to commercial polypropylene, and better flexibility and mechanical strength (39%, 6.7 MPa) compared to a glass fiber (GF) separator. The disordered mesoporous carbon/Na cell with a 16/12 PEI/PVP separator shows a high discharge capacity of 119.4 mAh g–1 at 0.5 C. Moreover, the cycling stability and rate performance of the sodium ion batteries is greatly enhanced using the prepared PEI/PVP as a separator. The enhanced electrochemical performance of the sodium ion batteries is attributed to the interconnected porous structure and high electrolyte uptake. These results suggest that the PEI/PVP separator is promising for safe and high performance sodium ion batteries.

The Progress of Hard Carbon as an Anode Material in Sodium-Ion Batteries

“…The PEI/PVP separator exhibited high ionic conductivity (1.14 mS cm −1 ), excellent thermal stability (over 180 °C), and outstanding flexibility and mechanical strength. The carbon/Na cell showed a high reversible capacity of 119.4 mAh g −1 at 0.5 C and good cycling performance [ 117 ]. Zhou et al prepared all-cellulose composite (ACC) separators coated with Zn 5 (OH) 8 Cl 2 ⋅H 2 O (ZHC) particles ( Figure 9 b).…”

Recent advances in modified commercial separators for lithium–sulfur batteries

“…344 Nonwoven membranes are oen made from poly(vinylidene) uoride (PVDF) 345 or polyimide, 346 and electrospun membranes can be made from various polymers like polyacrylonitrile (PAN) 347 and polyvinylpyrrolidone (PVP). 348 However, such membranes tend to have limited LiPS rejection capabilities and high cost of fabrication. 349 More work into optimizing ber roughness, 350,351 polymer blend ratios, 352 ber coating, 353,354 and nanomaterial doping [355][356][357] may open up solutions to improved ber-based separators for LSBs.…”

Paper-Based Composite Separator with Thermotolerant and Flame-Retardant Sodium Silicate Sheath for High-Performance Sodium-Ion Batteries

“…The well-designed battery-grade separators generally rely on balancing several properties such as wettability, porosity and void distribution, thickness, electrolyte absorption capacity, dimensional thermal stability, mechanical properties, and flame retardancy. − The polyolefin separators currently leading the secondary battery market have outstanding advantages such as low cost, good mechanical strength, and flexibility. However, the inherent molecular nonpolarity of polyolefin separators and their low porosity due to dry and wet processing methods are not conducive to the absorption and wetting of liquid electrolytes by the separator.…”