3D Grid of Carbon Tubes with Mn₃O₄-NPs/CNTs Filled in their Inner Cavity as Ultrahigh-Rate and Stable Lithium Anode

Transition metal oxides are regarded as promising candidates of anode for next-generation lithium-ion batteries (LIBs) due to their ultrahigh theoretical capacity and low cost, but are restricted by their low conductivity and large volume expansion during Li⁺ intercalation. Herein, we designed and constructed a structurally integrated 3D carbon tube (3D-CT) grid film with Mn₃O₄ nanoparticles (Mn₃O₄-NPs) and carbon nanotubes (CNTs) filled in the inner cavity of CTs (denoted as Mn₃O₄-NPs/CNTs@3D-CT) as high-performance free-standing anode for LIBs. The Mn₃O₄-NPs/CNTs@3D-CT grid with Mn₃O₄-NPs filled in the inner cavity of 3D-CT not only afford sufficient space to overcome the damage caused by the volume expansion of Mn₃O₄-NPs during charge and discharge processes, but also achieves highly efficient channels for the fast transport of both electrons and Li⁺ during cycling, thus offering outstanding electrochemical performance (865 mAh g⁻¹ at 1 A g⁻¹ after 300 cycles) and excellent rate capability (418 mAh g⁻¹ at 4 A g⁻¹) based on the total mass of electrode. The unique 3D-CT framework structure would open up a new route to the highly stable, high-capacity, and excellent cycle and high-rate performance free-standing electrodes for high-performance Li-ion storage.