“…However, common iron oxides oen undergo large volume changes (193% for Fe 2 O 3 , calculated from the densities of Fe 2 O 3 , Fe and Li 2 O) based on their electrochemical reactions in the charging-discharging process, 12,13 which can cause crushing of the crystal and aggregation of particles and lead to almost constantly falling capacity decay during the initial few cycles. Fortunately, the electrochemical performance can be effectively improved by combining iron oxides with conducting materials 14 such as reduced graphene oxide (rGO), [15][16][17][18] carbon, [19][20][21][22] carbon nanobers (CNFs), 23,24 carbon nanotubes, 25,26 and conductive polymers. 27,28 Coating carbon materials or conductive polymers can x the locations of iron oxides in the composite electrode, buffer the volume expansion and shrinkage, and retain the integrity of the crystal structures.…”