Reversible capacity enhancement of zinc-manganese mixed oxide through nanoscale electrochemicalwiring with carbon nanotubes

Zinc-manganese mixed oxide (ZMO)/carbon nanotube (CNT) composites are synthesized based on an electronic wiring design for use in Li-ion batteries. The resulting composite consists ofZMOnanoparticles in intimate contact with CNT. The ZMOnanoparticles, which are in the electrical wiring with the CNTs, exhibit an additional conversion reaction involving MnO/Mn₃O₄, resulting in an enhanced reversible capacity up to 1050 mA h g^-1, which exceeds the theoretical reversible capacity of ZnMn₂O₄ (780 mA h g^-1). During the synthesis of the ZMO/CNT composite, calcination in the presence of NH₃ gas not only inhibits the oxidative decomposition of the CNTs but also reduces the oxidation state of Mn in the resulting composite. The elimination of superfluous oxygen (decrease in oxidation state of Mn in ZMO) leads to a decrease in irreversible capacities during the first cycle, directly related to energy efficiency.