Tailoring the interfaces of silicon/carbon nanotube for high rate lithium-ion battery anodes

Abstract Micrometer-sized silicon powders, due to its high specific capacity, easy accessibility, and low cost, have been regarded as an attractive anode material for lithium-ion batteries. The severer mechanical instability and high inter-particle resistance during cycling, however, hinder its further application. In this work, a novel potholed micrometer-sized silicon powders (PMSi)/carbon nanotubes (CNT)/C electrode is proposed. The resulting three-dimensional (3D) conductive framework and multi-point contact network exhibit ideal structural stability and high-rate cycling property. Hence, the volume resistivity of PMSi/CNT/C (157 Ω m) is reduced significantly relative to traditional PMSi/commercial carbon nanotubes (CCT)/C composite (400 Ω m). By testing the fabricated half-cell LIB with the PMSi/CNT/C composite anode, high reversible specific capacity of 2533 mAh g−1 with a remarkable high initial coulombic efficiency of 89.07% and over 840 mA h g−1 for 1000 cycles at 2 A g−1 is measured. Even at the rate of 20 A g−1, the PMSi/CNT/C electrode shows a capacity of 463 mAh g−1. A full cell contained the PMSi/CNT/C anode and a LiFePO4/LiMn2O4 cathode successfully ignites an LED array (~1.5 W), further demonstrating its outstanding electrical driving property.