A biodegradable nano-composite membrane for high-safety and durable
lithium ion batteries
Abstract
As a key component of lithium-ion batteries (LIBs), separator plays a
crucial role in the performance and safety of LIBs. In this paper, a
cellulose based porous membrane modified by nano CaCO3 is prepared
conveniently by electrospinning. The membrane exhibits rich fibrous
porous networks and uniform distribution of nanoparticles. Strengthed by
CaCO3, the tensile strength of the cellulose porous membrane elevates
from 4.7 ± 0.4 MPa to 7.7 ± 0.7 MPa. Besides, the modified membranes
possess improved thermal stability and can maintain their original size
after treatment at 150 °C and 180 °C. Also, the electrolyte uptake of
cellulose/CaCO3 membrane is 73% higher than that of the pure cellulose
membrane. Thus, the ionic conductivity of membrane achieves 1.08 mS cm-1
and the electrochemical window is about 4.8V, which meets the practical
requirements of LIBs. Significantly, LiFePO4/Li battery this membrane
can run for 230 cycles with a capacity retention of 97.4% and a
discharge capacity of 149.0 mAh g-1, demonstrating the huge potential
for high safety and next-generation LIBs.