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

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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 a pore-forming agent and lithium source to create controllable pores in the 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 mA h 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 easily-prepared Si anodes for Li-ion batteries.