β-FeOOH nanorods enriched with bulk chloride as lithium-ion battery cathodes

β-FeOOH nanostructures have been synthesized under hydrothermal conditions at 80 °C for 4 h using ferric chloride and urea as reactants. After being aged for 3 days, chloride ions are loaded into the bulk of β-FeOOH to achieve superior electrochemical properties. β-FeOOH nanorods enriched with bulk chloride deliver a discharge capacity of 267 mAh g−1 at 0.05 C, and after 40 cycles, the discharge capacity remains 92.8%.