Thermally Cross-Linkable Diamino-Polyethylene Glycol Additive with Polymeric Binder for Stable Cyclability of Silicon Nanoparticle Based Negative Electrodes in Lithium Ion Batteries

Abstract

We developed a new type of additive with poly(acrylic acid) (PAA) for stable cycling retention of silicon anodes. Diamino-Polyethylene Glycol (diamino-PEG) is used as a thermally curable additive with PAA polymeric binder for silicon nanoparticle based negative electrodes. Amino groups of the diamino-PEG form amide bonds with carboxylic acid groups of the PAA binder, which gives strong binding force even under high humidity. The highly cross linked amide bonds between diamino-PEG and PAA binder in silicon nanoparticle based negative electrodes leads to reduced electrical contact loss of silicon particles during electrochemical reaction. It also supports stable cycling performance and enhances specific capacity compared to the case of using only a silicon anode PAA binder.