Graphenenanosheet–titanium nitride nanocomposite for high performance electrochemical capacitors without extra conductive agent addition

Abstract

A graphene nanosheet–titanium nitride (G–TiN) nanocomposite has been fabricated through a simple in situ hydrolysis method combined with ammonia annealing. TiN nanoparticles are homogeneously anchored on G, which is beneficial for the formation of a porous structure and the enhancement of electrical conductivity perpendicular to the graphene layers. Such a texture allows for the fast accessibility of ions and rapid transfer of electrons. In 1 M LiPF₆–EC : DEC (vol. 1 : 1) electrolyte, the specific capacitances of the electrochemical capacitors (ECs) assembled without extra conductive agent addition, are 560 and 132 F g⁻¹ at current densities of 0.1 and 4 A g⁻¹, respectively. Meanwhile, high energy densities of 162 and 81 W h kg⁻¹ are obtained at power densities of 150 and 934 W kg⁻¹, respectively. Even at a higher power density of 4367 W kg⁻¹, a remarkable energy density of 41 W h kg⁻¹ is delivered. The unique characteristic of G–TiN endows the ECs with high energy density and power density, due to the combination of electric double layer capacitance and lithium ion intercalation capacitance.