β-MnO2/Metal-Organic Framework Derived Nanoporous ZnMn2O4 Nanorods as Lithium-Ion Battery Anodes with Superior Lithium-Storage Performance

Nanoporous ZnMn2O4 nanorods have been successfully synthesized by calcining beta-MnO2/ZIF-8 precursors (ZIF-8 is a type of metal-organic framework). If measured as an anode material for lithium-ion batteries, the ZnMn2O4 nanorods exhibit an initial discharge capacity of 1792 mA h g(-1) at 200 mA g(-1), and an excellent reversible capacity of 1399.8 mA h g(-1) after 150 cycles (78.1 % retention of the initial discharge capacity). Even at 1000 mA g(-1), the reversible capacity is still as high as 998.7 mA h g(-1) after 300 cycles. The remarkable lithium-storage performance is attributed to the one-dimensional nanoporous structure. The nanoporous architecture not only allows more lithium ions to be stored, which provides additional interfacial lithium-storage capacity, but also buffers the volume changes, to a certain degree, during the Li+ insertion/extraction process. The results demonstrate that nanoporous ZnMn2O4 nanorods with superior lithium-storage performance have the potential to be candidates for commercial anode materials in lithium-ion batteries.