Facile synthesis of N/O dual-doped carbon spheres with excellent electrochemical performance

Abstract

Sodium ion battery is a new energy star to meet carbon neutrality idea due to abundant resources and low price. The exploration of proper anode materials to accommodate Na+ is a significant research subject. Here, N/O dual-doped carbon spheres (NOCS) derived from polyaniline have been easily prepared via pyrolysis treatment of polyaniline spheres (PS). When applied as an anode material for SIBs, NOCS shows the superior capacity (314 mAh g−1 at 50 mA g−1), good rate performance (139 mAh g−1 at 2 A g−1) and excellent structural stability. The great electrochemical capacity of NOCS can be attributed to the unique spherical structure, large carbon interlayer distance (0.375 nm), proper specific surface area (211 m2 g−1) and abundant heteroatom content (6.27 at% of nitrogen and 14.88 at% of oxygen). NOCS also displays excellent capacitance (104.4 F g−1 at 20 A g−1) and long cycling life (145.4 F g−1 at 1 A g−1 after 5000 cycles) as an electrode material for supercapacitors. These results illustrate that designing structure and composition will effectively promote the electrochemical properties of carbon materials.