The film properties of lithium-ion batteries determine the capacity, cycling stability, and other important battery characteristics, and therefore the diaphragm must have an adequate thickness, ionic conductivity, high porosity, and both thermal and electrochemical stability [ 4, 5, 6 ].
The discharge capacity of lithium-ion batteries assembled with PU/PAN fiber diaphragms was higher than that of the Celgard 2400 diaphragm at 0.2 C, 0.5 C, 1 C, 2 C, and 5 C rates. The lowest discharge capacity was recorded for lithium-ion batteries fitted with a Celgard 2400 diaphragm.
A high electrochemical stability window facilitates the long-term stable operation of Li-ion batteries at a high voltage. To evaluate the electrochemical stability of the diaphragm, the potential range was set to 2.5 V–6.0 V to perform LSV tests on the Celgard 2400 and PU/PAN fiber diaphragms.
Conclusions A centrifugal spinning method was used to prepare a PU/PAN lithium-ion battery diaphragm by blending with different ratios of PAN. The properties of the PU/PAN lithium-ion battery diaphragms were characterized in this study.
Analysis of Electrochemical Stability Electrochemical stability is an important performance parameter for lithium-ion battery diaphragms, which must maintain the stability of the electrolyte and electrode in terms of electrochemical properties to avoid degradation during the charge and discharge process.
In lithium-ion batteries assembled with LiFePO 4 as the cathode material, after 50 cycles at 0.2 C rate, the discharge specific capacity of the PU/PAN lithium-ion battery diaphragm could still be maintained at 147.1 mAh/g, with a capacity retention rate of 95.8%.