Corn-like Si derived from sepiolite as anode for advanced lithium-ion batteries

Low initial coulombic efficiency (ICE) and poor long-term cycling performance are key issues of silicon (Si) anode for lithium-ion batteries (LIBs), due to the irreversible consumption of Li ion. Herein, Si with corn-like structure is synthesized by a simple and low cost magnesiothermic reduction method from pre-treated sepiolite ore. The ICE of corn-like Si reaches 75.1 % and can be increased to almost 100 % by a simple surface prelithiated engineering, meanwhile the charge capacity remains 788 mA h·g-1 (0.56 mAh·cm-2) after 500 cycles at 1 A·g-1(0.71 mA·cm-2). Further SEM observation reveals that the prelithiated Si electrode keeps the original corn-like structure during cycling, confirming that available-Si from natural clay is applicable for the production of LIBs.