Copper-doping enhanced electrochemical performance of cobalt embedded nitrogen-doped porous carbon dodecahedra in lithium-ion half/full batteries

Abstract

The creation of negative electrode materials that have quick redox kinetics, reduced volumetric expansion, and a high reversible specific capacity is the linchpin to the advancement of lithium-ion batteries. Here, we prepared copper-doping cobalt-embedded nitrogen-doped porous carbon (CoCu@NC) by calcining copper-modified ZIF-67. The unique hollow structure presents a fast ionic diffusion channel and good structural stability. Density functional theory (DFT) calculation testifies that Cu-doping can regulate the electronic structure of the CoCu@NC surface as well as enhance lithium ions adsorption capacity on nitrogen sites. Furthermore, the presence of N and Cu could generate more defects, thereby achieving rapid storage reaction kinetics of lithium ions. Benefiting from the cooperative effect between Co and Cu double-doped at NC, strain and stress are alleviated during lithium-ion intercalation/deintercalation processes, thus improving cycling stability and performance. Therefore, CoCu@NC shows a superior capacity of 1155.10 mAh g−1 at a current density of 0.5 A g−1, and good stability with 310.90 mAh g−1 at 10 A g−1 after 600 cycles. The assembled LiCoO2//CoCu@NC-7 lithium-ion full battery can achieve a discharge-specific capacity at 3 A g−1 for 182.60 mAh g−1 after 500 cycles.