Facile synthesis of self-supported Mn3O4@C nanotube arrays constituting an ultrastable and high-rate anode for flexible Li-ion batteries

An advanced electrode is essential for flexible energy storage devices which enable the application of next-generation flexible electronics. In the current research project, we have designed and fabricated self-supported Mn3O4@C nanotube arrays on a conductive substrate via a simple template-assisted route, which can be directly used as a binder-free anode for flexible Li-ion batteries. Such microstructure engineering of electroactive Mn3O4 and conductive carbon layers enables the Mn3O4@C electrode to possess a high electrical conductivity. The substantial void space in the hollow nanotube and the gap between these 1D nanotube units allow for the full expansion of Mn3O4 while preserving the structural integrity of the Mn3O4@C self-supported electrode and stable SEI film on the outside carbon surface. As for Li-ion batteries, these binder-free Mn3O4@C electrodes exhibit a superior cycling performance (after 3000 cycles at 200 mA cm(-2)/793 mA g(-1) with a capacity retention of 552.2 mA h g(-1)) and excellent rate performance (a reversible capacity of 420, 400 and 375 mA h g(-1) at 400/1586, 500/1982 and 600/2380 mA cm(-2)/mA g(-1), respectively). The self-supported Mn3O4@C nanotube electrode with high flexibility shows its great potential for flexible energy storage devices.