The Hoberman sphere is a stable and stretchable spatial structure with a unique design concept, which can be taken as the ideal prototype of the internal mechanical/conductive skeleton for the anode with large volume change. Herein, Mn3O4 nanoparticles are interlaced with a Hoberman sphere-like interconnected carbon nanotube (CNT) network via a facile self-assembly strategy in which Mn3O4 can "locally expand" in the CNT network, limit the volume expansion to the interior space, and maintain a stable outer surface of the hybrid particle. Furthermore, an ultrathin uniform ALD-coated TiO2 shell is adopted to stabilize the solid electrolyte interphase (SEI), provide high electron conductivity and lithium ion (Li+) diffusivity with lithiated LixTiO2, and enhance the reaction kinetics of the Mn3O4 by an "electron-density enhancement effect". With this design, the Mn3O4@CNT/TiO2 exhibits a high capacity of 1064 mAh g-1 at 0.1 A g-1, a stable cycling stability over 200 cycles, a superior rate capability, and a commercial-level areal capacity of 4.9 mAh cm-2. In this way, a novel electrode design strategy is achieved by the Hoberman sphere-like CNT design along with the in situ porous formation, which can not only achieve a high-performance anode for LIBs but also can be widely adapted in a variety of advanced electrode materials for alkali metal ion batteries.
Keywords: Mn3O4; TiO2; anode; atomic layer deposition; lithium ion battery.