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In the present study, a kind of solid polymer electrolyte (SPE) based on poly(vinylidene difluoride-co-hexafluoropropylene)/poly(methyl methacrylate) blends was prepared by a casting method to solve the safety problem of lithium secondary batteries. Owing to being plasticized with a room temperature ionic liquid, N-butyl-N′-methyl-imidiazolium hexafluorophosphate, the obtained SPE shows a thermal decomposition temperature over 300°C and an ionic conductivity close to 10−3 S cm−1. The SPE-3 sample, in which the weight of two polymers is equivalent, possesses an ionic conductivity of 0.45 × 10−3 S cm−1 at 25°C and presents an electrochemical window of 4.43 V. The ionic conductivity of the SPE-3 is as high as 1.73 × 10−3 S cm−1 at 75°C approaching to that of liquid electrolyte. The electrochemical performances of the Li/LiFePO4 cells confirmed its feasibility in lithium secondary batteries.

In this study, we prepare a kind of solid polymer electrolyte (SPE) based on N-ethyl-N′-methyl imidazolium tetrafluoroborate (EMIBF4), LiBF4 and poly(vinylidene difluoride-co-hexafluoropropylene) [P(VdF-HFP)] copolymer. The resultant SPE displays high thermal stability above 300 °C and high room temperature ionic conductivity near to 10−3 S cm−1. Its electrochemical properties are improved with incorporation of a zwitterionic salt 1-(1-methyl-3-imidazolium)propane-3-sulfonate (MIm3S). When the SPE contains 1.0 wt% of the MIm3S, it has a high ionic conductivity of 1.57 × 10−3 S cm−1 at room temperature, the maximum lithium ions transference number of 0.36 and the minimum apparent activation energy for ions transportation of 30.9 kJ mol−1. The charge–discharge performance of a Li4Ti5O12/SPE/LiCoO2 cell indicates the potential application of the as-prepared SPE in lithium ion batteries.

A macaroni-like Li 1.2 V 3 O 8 nanomaterial was directly prepared through a facile solution route using β-cyclodextrin (β-CD) as a template reagent. Its crystal structure was determined by the X-ray diffraction (XRD) pattern. From the scanning electron microscopy (SEM) and transmission electron microscopy (TEM) micrographs, we observed that the as-prepared Li 1.2 V 3 O 8 material consisted of the aggregated macaroni-like nanoparticles and showed a porous structure. The electrochemical properties of the as-prepared Li 1.2 V 3 O 8 in 1.0 M Li 2 SO 4 aqueous electrolyte were studied through cyclic voltammograms and charge–discharge measurements. The results revealed that the as-prepared Li 1.2 V 3 O 8 could deliver the initial specific capacities of 189, 140, and 101 mAh g −1 at 0.1, 0.5, and 1.0 C, respectively. It suggests that the as-prepared Li 1.2 V 3 O 8 should have an attractive future to be applied in aqueous rechargeable lithium battery (ARLB).

A foaming process was used to prepare porous polymer membranes (PPMs) based on poly(vinylidene diflouride-co-hexafluoropropylene) copolymer for lithium ion batteries. In this simple process, urea, the foaming agent, was decomposed into gases and was removed at an elevated temperature to get the porous structure within the polymer matrix. When the weight ratio of urea to P(VDF-HFP) is 5:6, the PPM presents the highest porosity, 70.2%, and the prepared gelled polymer electrolyte shows an ionic conductivity up to 1.43 × 10 −3 S cm −1 at room temperature. This provides another way to prepare gelled polymer electrolytes easily for application in rechargeable lithium batteries.

A kind of porous nanocomposite polymer membranes (NCPMs) based on poly(vinylidene difluoride-co-hexafluoropropylene) (P(VdF-HFP)) incorporated with different amounts of TiO 2 nanoparticles from in situ hydrolysis of Ti(OC 4 H 9 ) 4 was prepared by a non-solvent induced phase separation (NIPS) technology. The SEM micrographs reveal that a porous structure exists in the NCPMs, which changes with the incorporated amount of TiO 2 . The NCPMs incorporated with 9.0 wt.% of mass fraction of TiO 2 possess the highest porosity, 67.3%, and appear as flexile fracture with an elongation ratio, 74.4%. At this content, the ionic conductivity of the NCPE is up to 0.94 × 10 −3 S cm −1 at room temperature and the activation energy for ions transport reaches the lowest, 18.71 kJ mol −1 . It is of great potential application in lithium ion batteries.

A lotus root-like porous nanocomposite polymer electrolyte (NCPE) based on poly(vinylidene difluoride-co-hexafluoropropylene) [P(VDF-HFP)] copolymer and TiO2 nanoparticles was easily prepared by a non-solvent induced phase separation (NIPS) process. The formation mechanism of the lotus root-like porous structure is explained by a qualitative ternary phase diagram. The resulting NCPE had a high ionic conductivity up to 1.21 × 10−3 S cm−1 at room temperature, and exhibited a high electrochemical stability potential of 5.52 V (vs. Li/Li+), lithium ion transference number of 0.65 and 22.89 kJ mol−1 for the apparent activation energy for transportation of ions. It is of great potential application in polymer lithium ion batteries. Keywords: Lotus root, Nanocomposite polymer, Porous membranes, P(VDF-HFP), Phase separation