Sub-nanometer structured silicon-carbon composite nanolayers armoring on graphite for fast-charging and high-energy-density lithium-ion batteries

摘要

Silicon/carbon composites are promising alternatives to current graphite anodes in commercial lithiumion batteries(LIBs)because of their high capacity and excellent safety.Nevertheless,the unsatisfactory fastcharging capability and cycle stability of Si/C composites caused by slow charge transport capability and huge volume change under industrial electrode conditions severely hamper their development.Here,a novel Si/C anode was fabricated by homogeneously depositing amorphous C-Si nanolayers on graphite(C-Si@graphite).C-Si nanolayers with uniformly dispersed sub-nanometer Si particles in 3D carbon skeleton significantly boost electron and Li-ion transport and efficiently relieve Si's agglomeration and volume change.As a result,the tailored C-Si@graphite electrodes show an excellent rate capacity(760.3 mAh·g^(-1)at 5.0C)and long cycle life of over 1000 cycles at 1.0C and800 cycles at 2.0C under industrial electrode conditions.In addition,the assembled full cells(C-Si@graphite,anode;Li[Ni_(0.8)Co_(0.1)Mn_(0.1)]O_(2),cathode)present superior fastcharging capability(240.4 Wh·kg^(-1),charging for16.2 min,3.0C)and long cycle life(80.7%capacity retention after 500 cycles at 1.0C),demonstrating the massive potential of C-Si@graphite for practical application.