High‐performance nano‐TiO₂@polyvinylidene fluoride composite separators prepared by electrospinning for safe lithium‐ion battery

Abstract

Traditional polyolefin separators cannot guarantee safety for lithium-ion batteries at high temperature due to their low melting point, especially for high power discharge. Therefore, it is imperative to develop separators with excellent thermal stability. In this paper, we have prepared TiO 2 modified PVDF composite separators by electrospinning. When compared with commercial PE separators, this kind of composite separators show superior thermal stability at 160 C. In addition, it is found that the 0.5-TiO 2 @PVDF separator exhibits excellent flame retardant and optimal tension strength. Meanwhile, the 0.5-TiO 2 @PVDF separator exhibits ideal liquid electrolyte storage capacity, which improves the ionic conductivity (0.68 mS cm À1 ). As a result, the LiCoO 2 jjLi cells with 0.5-TiO 2 @PVDF separator have high discharge capacity retention rate at a current density of 1 C (300 cycles) and excellent rate performance (1.75 mAh at 5 C). In short, nano-TiO 2 modified PVDF separator has a great application prospect in high-performance and high-safety lithium-ion batteries.

Coaxial Electrospun Tai Chi-Inspired Lithium-Ion Battery Separator with High Performance and Fireproofing Capacity

“…The electrochemical capacity of the separator was further explored. Good wettability of separator is the key to improve the electrochemical performance . The contact angles of the PVDF, PVDF@TPP, TPP@PVDF/SiO 2 /GO, and Celgard2325 separators to the electrolyte were 32.02°, 37.43°, 0, and 42.72°, respectively, as shown in Figure a, indicating that GO and SiO 2 greatly improved the hydrophilicity of the separator due to large numbers of the OH group .…”

“…Good wettability of separator is the key to improve the electrochemical performance. 21 The contact angles of the PVDF, PVDF@TPP, TPP@PVDF/SiO 2 /GO, and Cel-gard2325 separators to the electrolyte were 32.02°, 37.43°, 0, and 42.72°, respectively, as shown in Figure 4a, indicating that GO and SiO 2 greatly improved the hydrophilicity of the separator due to large numbers of the OH group. 50 On the other hand, the large porosity and liquid absorbency of the separator contribute to the rapid absorption of liquid electrolyte and thus improve the electrochemical performance.…”

“…In this paper, inspired by Tai Chi, a “powerful” and fireproofing core–shell membrane was fabricated by one-step coaxial electrospinning and used as a battery separator, where the core layer was TPP, and the shell layer was a mixture of PVDF, SiO 2 , and GO (thereafter called TPP@PVDF/SiO 2 /GO). PVDF , is currently the most studied nanofibrous separator material because of its excellent affinity for organic electrolytes, good chemical stability, and unique fluorine group (−F), facilitating the migration of lithium ions; GO , is one of the most important graphene derivatives, which has excellent mechanical properties, can promote the penetration of lithium ions, and is also an effective inorganic flame retardant . SiO 2 is a hydrophilic fireproof material that can effectively improve electrochemical performance.…”

The sustainable recycling of polyvinylidene fluoride membrane for tribological application

“…In addition to alleviating the problem of resource shortage and mitigating environmental pollution, waste reuse can also help enterprises to achieve sustainable production and obtain longterm economic benefits. 1,2 Polyvinylidene fluoride (PVDF) is a highly sought-after material in the fields of water pollutant removal, 3,4 lithium-ion batteries, 5 and tribology 6 due to the merits of excellent chemical stability, high hydrophobicity, high mechanical strength, and so forth. Generally, PVDF is often used to prepare membranes for water treatment due to its good film-forming properties and chemical stability, but the surface hydrophobicity and the inferior anti-fouling performance of PVDF membrane takes place easily, 7,8 and thereby shortening its service life.…”

Batch Fabrication of Electrospun PAN/PU Composite Separators for Safe Lithium-Ion Batteries

“…Presently, the polymers used in electrospun nanofiber separators include polyacrylonitrile (PAN) [20][21][22], polyimide (PI) [23][24][25], polyvinylidene fluoride (PVDF) [26][27][28], and so on [29,30]. Among them, PAN exhibits superior thermal stability at high temperatures due to its high melting point, and its nitrile group (-CN) facilitates the dissociation of lithium ions in electrolytes [31].…”