Lun Peiqi, Chen Zilong, Zhang Zhenbao, Tan Shaozao, Chen Dengjie
Guangdong Engineering & Technology Research Centre of Graphene-like Materials and Products, Department of Chemistry, College of Chemistry and Materials Science, Jinan University Guangzhou 510632 China
RSC Adv. 2018 Oct 5;8(60):34232-34240. doi: 10.1039/c8ra06856a. eCollection 2018 Oct 4.
Solid composite electrolytes have gained increased attention, thanks to the improved safety, the prolonged service life, and the effective suppression on the lithium dendrites. However, a low ionic conductivity (<10 S cm) of solid composite electrolytes at room temperature needs to be greatly enhanced. In this work, we employ natural halloysite nanotubes (HNTs) and poly(vinylidene fluoride) (PVDF) to fabricate composite polymer electrolytes (CPEs). CPE-5 (HNTs 5 wt%) shows an ionic conductivity of ∼3.5 × 10 S cm, which is ∼10 times higher than the CPE-0 (without the addition of HNTs) at 30 °C. The greatly increased ionic conductivity is attributed to the negatively-charged outer surface and a high specific surface area of HNTs, which facilitates the migration of Li in PVDF. To make a further illustration, a solid-state lithium-ion battery with CPE-5 electrolyte, LiMnO cathode and Li metal anode was fabricated. An initial discharge capacity of ∼71.9 mA h g at 30 °C in 1C is obtained, and after 250 cycles, the capacity of 73.5 mA h g is still maintained. This study suggests that a composite polymer electrolyte with high conductivity can be realized by introducing natural HNTs, and can be potentially applied in solid-state lithium-ion batteries.
固态复合电解质因其安全性提高、使用寿命延长以及对锂枝晶的有效抑制而受到越来越多的关注。然而，固态复合电解质在室温下的低离子电导率（<10 S cm）需要大幅提高。在这项工作中，我们采用天然埃洛石纳米管（HNTs）和聚偏氟乙烯（PVDF）来制备复合聚合物电解质（CPEs）。CPE-5（HNTs含量为5 wt%）在30°C时的离子电导率约为3.5×10 S cm，比CPE-0（未添加HNTs）高出约10倍。离子电导率的大幅提高归因于HNTs带负电荷的外表面和高比表面积，这有利于Li在PVDF中的迁移。为了进一步说明，制备了一种采用CPE-5电解质、LiMnO阴极和Li金属阳极的固态锂离子电池。在30°C下以1C倍率放电时，初始放电容量约为71.9 mA h g，经过250次循环后，容量仍保持在73.5 mA h g。这项研究表明，通过引入天然HNTs可以实现具有高电导率的复合聚合物电解质，并有可能应用于固态锂离子电池。
