All-Integrated Bifunctional Separator for Li Dendrite Detection via Novel Solution Synthesis of a Thermostable Polyimide Separator

Abstract

Safe operation is crucial for lithium (Li) batteries, and therefore, developing separators with dendrite-detection function is of great scientific and technological interest. However, challenges have been encountered when integrating the function into commercial polyolefin separators. Among all polymer candidates, polyimides (PIs) are prominent due to their good thermal/mechanical stability and electrolyte wettability. Nevertheless, it is still a challenge to efficiently synthesize PI separators, let alone integrate additional functions. In this work, a novel yet facile solution synthesis was developed to fabricate a nanoporous PI separator. Specifically, recyclable LiBr was utilized as the template for nanopores creation while the polymer was processed at the intermediate stage. This method proves not only to be a facile synthesis with basic lab facility but also to have promising potential for low-cost industrial production. The as-synthesized PI separator exhibited excellent thermal/mechanical stability and electrolyte wettability, the latter of which further improves the ionic conductivity and thus battery rate capability. Notably, stable full-cell cycling for over 200 cycles with a PI separator was further achieved. Based on this method, the fabrication of an all-integrated PI/Cu/PI bifunctional separator for dendrite detection can be fulfilled. The as-fabricated all-integrated separators prove efficient as early alarms of Li penetration, opening up the opportunity for safer battery design by separator engineering.

Advanced Micro/Nanostructures for Lithium Metal Anodes

“…Nanoprous PI,79 polyoxyzole nanofiber membranes,80 Janus separator with mesoporous graphene,81 graphene/Nafion/PP,82 mussel‐inspired polydopamine‐coated separators,83 boron‐nitride coated separators,84 graphene/PP/Al 2 O 3 composite separators,85 and garnet nanoparticles/polyethylene oxide membrane electrolytes86 are also effective to retard the formation of Li dendrites.…”

Lithiophilic Sites in Doped Graphene Guide Uniform Lithium Nucleation for Dendrite‐Free Lithium Metal Anodes

“…[1,2] Since the Li metal anode possesses an ultrahigh theoretical specific capacity (3860 mA hg À1 )a nd the lowest negative electrochemical potential (À3.040 Vv s. the standard hydrogen electrode), Li metal batteries (LMBs) are therefore recognized as one of the most promising candidates. [1,3] Therefore,Lidendrites and their related issues severely hinder the practical applications of LMBs. To address these issues,s ignificant progress has been achieved recently,i na reas including liquid electrolyte modifications, [4] artificial electrode/electrolyte films, [5] solid-state [6] or polymer [7] electrolytes,h ybrid electrolytes, [8] and nanostructured anodes with high surface areas. [1,3] Therefore,Lidendrites and their related issues severely hinder the practical applications of LMBs. To address these issues,s ignificant progress has been achieved recently,i na reas including liquid electrolyte modifications, [4] artificial electrode/electrolyte films, [5] solid-state [6] or polymer [7] electrolytes,h ybrid electrolytes, [8] and nanostructured anodes with high surface areas.…”

High Uptake and Fast Transportation of LiPF6 in a Porous Aromatic Framework for Solid‐State Li‐Ion Batteries

“…When the current density was switched back to 0.2C, a capacity of 148 mAh g −1 is recovered. These results showed that the LiFePO 4 ∥LiPF 6 @PAF‐1∥Li cell have superior performance in the wide current range and were suitable for the high rate application of Li‐ion batteries . The voltage versus time profiles of the battery under each current density corresponding to the rate capacity test were shown in Figure e. The voltage profiles were very stable, and there was no obvious fluctuation under different current densities, indicating good circularity and stable interface of the battery .…”