Hollow Nanoporous Multishelled NiCo₂O₄ Spheres for Lithium-Ion Batteries

Lithium-ion batteries (LIBs) have fallen short of expectation in terms of energy density compared to conventional lithium-ion batteries, and the theoretical energy density of the anode material plays a crucial role. Materials with high equilibrium effective specific surface area and mass transport could be promising to solve the dilemma. Herein, we develop a tactic to synthesize carbonaceous microspheres (CMSs, 13 μm) utilizing cobalt acetate tetrahydrate as the catalyst. Six-shelled NiCo2O4 hollow multishelled structures (6S-NiCo2O4-HoMSs) have been realized for the first time based on the alkali-treated CMS (ATCMS) template with nanoporous structures. Precisely, low-dimensional nanostructures enable more electroactive sites, smaller local current density, and shorter diffusion paths for both ions and electrons. The particular hollow multishelled structure serves to buffer the volume expansion, reduce the stress and strain to permit more uniform lithium deposition, and improve the cycle stability of the battery.