Low-cost route to porous silicon is key to improving Li-ion batteries

Lithium-ion batteries are commonly found in portable electronics and electric or hybrid cars and have traditionally contained a graphite anode. Silicon has since emerged as a promising anode substitute because it is the second most abundant element on earth and has a theoretical capacity of 3,600 milliamp hours per gram (mAh/g), almost 10 times the capacity of graphite.

The capacity of a lithium-ion battery is determined by how many lithium ions can be stored in the cathode and anode. Using silicon in the anode increases the battery’s capacity because one silicon atom can bond up to 3.75 lithium ions, whereas with a graphite anode six carbon atoms are needed for every lithium atom.

The USC Viterbi team developed a commercially viable silicon anode with a stable capacity above 1100mAh/g for extended 600 cycles, making their anode nearly three times more powerful and longer lasting than a typical commercial anode.