Co-synthesis and Electrochemical Investigation of the Nitrogen-Doped Carbon Layer with Metallic Nano Beads on the SiO x Anode for Lithium Secondary Batteries.

The high theoretical capacity (∼2000 mAh g -1 ) of silicon suboxide (SiO x , with 1 < x < 2) can solve the energy density issue of the graphite anode in Li-ion batteries. In addition, it has an advantage in terms of volume expansion or side reactions compared to pure Si or Li metals, which are considered as next-generation anode materials. However, the loading content of SiO x is limited in commercial anodes because of its low cycle stability and initial coulombic efficiency. In this study, a nitrogen-doped carbon layer with Cu beads (N-C/Cu) derived from copper phthalocyanine (CuPc) is applied to a SiO x electrode to improve its electrochemical performance. The SiO x electrode is simultaneously coated with a Cu- and N-doped carbon layer using CuPc. N-C/Cu synergistically enhances the electric conductivity of the electrode, thus improving its electrochemical performance. The SiO x /N-C/Cu composite has better cyclability and higher capacity (1095.5 mAh g -1 ) than the uncoated electrode, even after 200 cycles in the 0.5 C condition. In full-cell cycling with NCM811 cathodes, the SiO x (60 wt % of SiO x , with a n/p ratio of 1.1) and graphite-mixed (7.8 wt % of SiO x , with a n/p ratio of 1.1) anodes also show improved electrochemical performances in the same conditions.