Improved battery safety via in-situ dip-coated composite gel polymer electrolytes
Abstract
A new type of PVC-CPVC-MBS-B44 composite gel polymer electrolyte (GPE), based on LiTFSI and incorporated with nano-silica, is designed. The adhesion of the electrolyte membranes is improved by introducing B44, with its excellent adhesion ability, into the GPEs. The GPE membrane is coated on the anodes by an in-situ dip-coating process for battery assembly, reducing the interfacial resistance of the battery. The PVC-CPVC-MBS-B44 composite GPE exhibits superior electrochemical performance. The electrochemical window is over 4.9 V (vs. Li/Li+), the ion conductivity is 0.96 × 10- 3 S cm-1 at an ambient temperature, and the lithium ion transference number is 0.61. The LiCoO2/PVC-CPVC-MBS-B44 composite GPE/graphite cells exhibit maximum discharge capacities of approximately 137.98, 136.5, and 129.4 mAh g-1 at 0.2C, 0.5C, and 1C discharge rates, respectively. The cells with GPE can maintain a high discharge capacity of 116 mAh g-1 and a capacity retention exceeding 82.9% after 200 cycles at 0.5C. Heavy impact, nail penetration, crush test, short-circuit test, drop test and heating test are carried out on 1-Ah GPE pouch cells, and the battery does not ignite nor smoke. A battery prepared using the proposed approach can deliver outstanding safety, high rate capabilities, and superior cycle stability, making it a potential candidate for various applications.
- Publication:
-
Journal of Power Sources
- Pub Date:
- April 2020
- DOI:
- 10.1016/j.jpowsour.2020.227963
- Bibcode:
- 2020JPS...45527963P
- Keywords:
-
- Gel polymer electrolyte;
- Composite;
- Dip-coating;
- Lithium ion battery;
- Battery safety