Engineering a dual-porous Li-rich carbon coated Si/SiOx nanosphere as high-performance Li-ion battery anode

Abstract

Silicon (Si)-based anodes receive broad attention for high energy-density lithium-ion batteries. However, huge volumetric expansion occurs during lithiation. Moreover, the loss of Li+ ions during cycling remains a challenge. Here, we develop a dual-porous carbon-coated Si (DP Si/SiOx@Li-C) using pore-forming agent and lithium source to create controllable pores in carbon layer of porous Si/SiOx, and supply Li+ to the anode. The dually porous structure accommodates the volumetric change and enables rapid ion transfer, while supplying abundant Li+ ions. The DP Si/SiOx@Li-C anode exhibits a stable capacity of 809.8 mAh g-1 after 100 cycles at 0.1 A g-1; with a decay rate of only 0.093% per cycle, and a Coulombic efficiency exceeding 99.2% when cycling 350 times at 0.5 A g-1. These findings provide a new strategy for developing stable and easy-preparing Si anodes for Li-ion batteries.