Modified cellulose-based separator with high transference number and uniform lithium deposition for dendrite-free lithium metal batteries

Abstract

The demand for high-performance lithium-ion batteries has increased significantly due to the rapid growth of portable electronic devices and new energy vehicles. The separator, an essential component of the battery, directly impacts the safety and cycle performance of the battery. A novel lithium-ion battery separator was fabricated by applying acid-modified halloysite nanotubes (NHNTs) onto cellulose paper (CP). Following the etching process of HNTs using sulfuric acid, the interior cavity of the tubular structure enlarges, creating more pathways for the movement Li⁺ ions. This facilitates the even distribution of Li⁺ ions and prevents the formation of lithium dendrites. Furthermore, cellulose paper has a significant quantity of hydroxyl groups, which enhances its attraction to the electrolyte. As a result, the NHNTs separator that is produced exhibits exceptional electrolyte absorption rate, commendable thermal stability, and superior mechanical properties. The LiFePO₄/NHNTs separator/Li battery has exceptional rate performance, with a charging and discharging capacity of 113 mAh g⁻¹ at 5C. Additionally, it demonstrates good cycle performance, maintaining a capacity retention rate of 95.5% after 500 cycles at 1C.