Ionic liquid-derivatized hierarchical N-doped carbon-coated Co_3O_4 nanosheet array as high-performance anode materials for lithium-ion batteries

摘要

A novel nitrogen-doped carbon-coated graded Co_3O_4 nanosheets (NDC/Co_3O_4 NS) is synthesized by using a simple ionic liquid hydrothermal method. The as-prepared NDC/Co_3O_4 NS is composed of hexagonal nanosheets having different orientation and the thickness of 50-100 nm. Significantly, as an anode electrode for lithium-ion batteries (LIBs), the NDC/ CO_3O_4 NS performed excellent cyclability. The NDC/Co_3O_4 NS delivers an initial discharge capacity of 1281.4 mAh g~(-1) at 445 mA g~(-1) and maintains a reversible high capacity of 929.4 mAh g~(-1) after 50 cycles, much higher than the unmodified Co_3O_4 nanosheets (230 mAh g~(-1)). The superior excellent electrochemical performance can be attributed to the gradient structure and the nitrogen-doped carbon coating resulting in shorter ion transport distances and good electrical conductivity.