Haijun Cao

Polyhedral oligomeric silsesquioxane containing gel polymer electrolyte based on a PMMA matrix

The present research is based on two expectations: a polyhedral oligomeric silsesquioxane (POSS) nano-cage can endow gel polymer electrolyte (GPE) with similar properties as can be accomplished with other inorganic nanoparticles; and the organic substituents at the cage corners of POSS are more compatible with GPEs. Therefore, POSS, as a hybrid modification filler, was added into GPE within a polymethyl methacrylate (PMMA) matrix. The results indicated that the amount of POSS addition was a critical factor for the ionic conductivity of prepared GPEs. When the POSS content was 7.5 wt%, the thermal stability was sufficient at the elevated temperature; the ionic conductivity of GPE reached 2.0 × 10−3 S cm−1; the mechanism of conductivity followed typical Arrhenius behavior; the lithium ion transference number reached up to 0.33; the deposition/dissolution of lithium was highly reversible; the electrochemical stability window was high enough at 5.25 V and the compatibility with lithium electrolyte was satisfactory.

A gel polymer electrolyte based on a novel synthesized matrix of a self-doped polymer of h-poly(methyl methacrylate-vinyl trismethoxy silane)

In order to incorporate inorganic nano-particles into a gel polymer electrolyte (GPE) in the form of chemical bonds to improve electrolyte performances, monomers of methyl methacrylate (MMA) and vinyl trismethoxy silane (VTMS) were chosen to synthesize the novel self-doped polymer of h-poly(methyl methacrylate-vinyl trismethoxy silane) (h-P(MMA-VTMS)), and then the obtained polymer was used as a matrix to prepare GPE. By the characterization of the resultant polymer, the composition and structure conformed to the design concept, and the self-doped polymer is amorphous and possesses two different glass transition temperatures (Tg) and a better thermal stability. From the investigation of the prepared GPE, it is thermally stable in the temperature range from 30 °C to 100 °C and the ionic conductivity reaches the level of 10−4 S cm−1 at room temperature. For the 50 wt% GPE system, the variation in ionic conductivity displays an Arrhenius behavior in the temperature range from 30 °C to 60 °C. The higher lithium ion transference number is 0.42, the compatibility with lithium metal anode is better and the electrochemical stability is stable up to 5.2 V versus Li/Li+.

Adsorption of phenol with the crosslinked polymer of P(MMA-MAh)-PEG33

ABSTRACTThe adsorption of phenol with the crosslinked polymer of P(MMA-MAh)-PEG33 was studied. Through the research, it was found the adsorption was favored in acidic aqueous solution and almost needed 35 h to reach the equilibrium. The calculated thermodynamic parameters suggested that the adsorption of phenol onto P(MMA-MAh)-PEG33 was spontaneous and exothermic in nature. From the kinetic research, the adsorption of phenol with the crosslinked polymer belonged to the first-order reaction. The adsorption isotherms of phenol with polymer well accorded with the Freundlich model.