Template-free synthesis of hollow-structured Co3O4 nanoparticles as high-performance anodes for lithium-ion batteries.

We have developed a template-free procedure to synthesize Co3O4 hollow-structured nanoparticles on a Vulcan XC-72 carbon support. The material was synthesized via an impregnation-reduction method followed by air oxidation. In contrast to spherical particles, the hollow-structured Co3O4 nanoparticles exhibited excellent lithium storage capacity, rate capability, and cycling stability when used as the anode material in lithium-ion batteries. Electrochemical testing showed that the hollow-structured Co3O4 particles delivered a stable reversible capacity of about 880 mAh/g (near the theoretical capacity of 890 mAh/g) at a current density of 50 mA/g after 50 cycles. The superior electrochemical performance is attributed to its unique hollow structure, which combines nano- and microscale properties that facilitate electron transfer and enhance structural robustness.