Self-healing strategy for Si nanoparticles towards practical application as anode materials for Li-ion batteries

The overwhelming advantage of Si nanoparticles (SiNPs) over Si microsized particles (SiMPs) as anode materials is compromised by their severe side reactions with electrolyte and agglomeration during cycling. Unlike usual solutions such as surface encapsulation or coating, here, a new strategy was proposed by mimicking the self-healing ability of living organisms. Ureidopyrimidinone functionalized polyethylene glycol (UPy-PEG-UPy) was successfully synthesized. Taking it as binder, SiNPs achieved excellent electrochemical performance with an initial coulombic efficiency (ICE) as high as 81% and a reversible capacity of 1454 mAh/g after 400 cycles corresponding to an average capacity decay of 0.04% per cycle. This achievement is attributed to the self-healing ability of UPy-PEG-UPy, which enables to spontaneously heal micro-cracks on electrode prior to its propagation, therefore preventing Si particles agglomeration and maintaining electrode integrity.