Enhancement of the electrochemical performance of lithium-ion batteries by SiO2@poly(2-acrylamido-2-methylpropanesulfonic acid) nanosphere addition into a polypropylene membrane

Guoping Yang; Haopeng Cai; Xiangyu Li; Mengjun Wu; Xue Yin; Haining Zhang; Haolin Tang

doi:10.1039/c9ra08273e

Enhancement of the electrochemical performance of lithium-ion batteries by SiO₂@poly(2-acrylamido-2-methylpropanesulfonic acid) nanosphere addition into a polypropylene membrane

RSC Adv. 2020 Jan 30;10(9):5077-5087. doi: 10.1039/c9ra08273e. eCollection 2020 Jan 29.

Authors

Guoping Yang¹, Haopeng Cai^{1

2}, Xiangyu Li¹, Mengjun Wu³, Xue Yin¹, Haining Zhang³, Haolin Tang³

Affiliations

¹ School of Materials Science and Engineering, Wuhan University of Technology Wuhan 430070 China [email protected].
² Institute of Advanced Material Manufacturing Equipment and Technology, Wuhan University of Technology Wuhan 430070 People's Republic of China.
³ State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology Wuhan 430070 China [email protected].

Abstract

Employing electrostatic self-assembly and free radical polymerization, the surface of SiO₂ nanospheres was coated with poly(2-acrylamido-2-methylpropanesulfonic acid) (SiO₂@PAMPS) bearing strong electron withdrawing sulfonic and amide groups, enhancing the dissociation ability of the lithium salt of the liquid electrolyte and absorbing anions via hydrogen bonds. After SiO₂@PAMPS nanospheres were introduced into the polypropylene (PP) membrane (SiO₂@PAMPS/PP), the electrolyte affinity and electrolyte uptake of the composite separators were significantly improved. The ionic conductivity of SiO₂@PAMPS/PP-18% (where 18% represents the concentration of the solution used for coating) soaked in liquid electrolyte was even 0.728 mS cm^-1 at 30 °C, much higher than that of the pristine PP membrane. The LiFePO₄/Li half-cell with SiO₂@PAMPS/PP-18% had a discharge capacity of 148.10 mA h g^-1 and retained 98.67% of the original capacity even after 120 cycles at 0.5C. Even at a rate of 1.0C, the cell capacity could be maintained above 120 mA h g^-1. Therefore, a coating formula was developed that could considerably improve the cycling ability and high rate charge-discharge performance of lithium ion batteries.