Hierarchical NiCo 2 O 4 nanosheets grown on hollow carbon microspheres composites for advanced lithium-ion half and full batteries.

Hierarchical ultrathin NiCo ₂ O ₄ nanosheeets grown on uniform hollow carbon microspheres (HC@NiCo ₂ O ₄ ) are designed and fabricated by a solvothermal reaction followed with an annealing process. When evaluated as an anode for lithium ion batteries, the as-prepared HC@NiCo ₂ O ₄ microspheres exhibit excellent electrochemical performance (a high reversible capacity of 1015 mA h g ^-1 after 100 cycles at a current density of 0.1 A g ^-1 and a high capacity of 805 mA h g ^-1 even at a high current density of 0.5 A g ^-1 ). By pairing with the LiCoO ₂ cathode, the HC@NiCo ₂ O ₄ anode also manifests excellent performance in full cells. The outstanding electrochemical performance in half and full cells can be attributed to its unique structure, which can not only promote the contact of electrode and electrolyte during the charge and discharge processes, but also shorten the transmission path of electrons and ions. More importantly, this study inspires a better design of various metal oxide/carbon electrode materials for high performance lithium ion batteries.
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