The recovery of useful materials fr

The recovery of useful materials from earth-abundant substances is of strategic importance for industrial
processes. Despite the fact that Si is the second most abundant element in the Earth’s crust, processes to form
Si nanomaterials is usually complex, costly and energy-intensive. Here we show that pure Si nanoparticles
(SiNPs) can be derived directly from rice husks (RHs), an abundant agricultural byproduct produced at a
rate of 1.23108 tons/year, with a conversion yield as high as 5% by mass. And owing to their small size (10–
40 nm) and porous nature, these recovered SiNPs exhibits high performance as Li-ion battery anodes, with
high reversible capacity (2,790 mA h g21, seven times greater than graphite anodes) and long cycle life (86%
capacity retention over 300 cycles). Using RHs as the raw material source, overall energy-efficient, green,
and large scale synthesis of low-cost and functional Si nanomaterials is possible.