Novel Hoberman Sphere Design for Interlaced Mn₃O₄@CNT Architecture with Atomic Layer Deposition-Coated TiO₂ Overlayer as Advanced Anodes in Li-Ion Battery

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 Li_xTiO₂, 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.