Recent developments in natural mineral-based separators for lithium-ion batteries

Lithium-ion batteries (LIBs) are currently the most widely used portable energy storage devices due to their high energy density and long lifespan. The separator plays a key role in the battery, and its function is to prevent the two electrodes of the battery from contacting, causing the internal short circuit of the battery, and ensuring the lithium ions transportation. Currently, lithium ion battery separators widely used commercially are polyolefin separators, such as polyethylene (PE) and polypropylene (PP) based separators. However, polyolefin separators would shrink at high temperatures, causing battery safety issues, and also causing white pollution. To solve these issues, the use of natural minerals to prepare composite separators for LIBs has attracted widespread attention owing to their unique nano-porous structure, excellent thermal and mechanical stability and being environmentally friendly and low cost. In this review, we present recent application progress of natural minerals in separators for LIBs, including halloysite nanotubes, attapulgite, sepiolite, montmorillonite, zeolite and diatomite. Here, we also have a brief introduction to the basic requirements and properties of the separators in LIBs. Finally, a brief summary of recent developments in natural minerals in the separators is also discussed.