Molecular cooking: Amino acids trap silicon in carbon matrix to boost lithium-ion storage

Exploring facile and low-cost preparation route is desired for high-performance silicon@carbon (Si@C) anode. Here, the amino acid units of protein molecules in egg white trap modified Si nanoparticles (NPs) through a facile 'molecular cooking' strategy, followed by incorporating the Si NPs into a functional carbon skeleton at nanoscale through in situ carbonization. The relationship between fundamental structure and properties is well studied. Experimental results reveal that the outer N-doped carbon layer can not only provide sufficient electrical conductivity for Li-ion reaction kinetics but can also enhances the stability of the interface between the active material and the Cu collector. The inner SiO(x )layer shows good lithium affinity, which can optimise the Li-ion transport path. The double layer can effectively buffer the huge internal strain of the Si core. The resultant hybrid M-Si@SiOx @C composite with 32.4 wt% carbon content possessed superior rate capability (1062 mAh g(-1) at 6 A g(-1) ) and long-term stability (727 mAh g(-1) at 2 A g(-1) after 400 cycles). In addition, the fabricated full cell also demonstrated favourable Li-ion storage capability. This work provides a facile strategy for the preparation of other electrodes with serious continuous volumetric swelling-shrinking behaviour upon cycling.