A uniform few-layered carbon coating derived from self-assembled carboxylate monolayers capable of promoting the rate properties and durability of commercial TiO(2)

The poor cyclability and rate property of commercial TiO(2) (c-TiO(2)) hinder its utilization in lithium-ion batteries (LIBs). Coating carbon is one of the ways to ameliorate the electrochemical performance. However, how to effectively form a uniform thin carbon coating is still a challenge. On the basis of the strong interaction of the TiO(2) surface with carboxyl groups, herein a new tactic to achieve uniform and thin carbon layers on the c-TiO(2) particles was proposed. When mixing c-TiO(2) with citric acid containing carboxyl groups in deionized water, the high-affinity adsorption of TiO(2) for carboxyl groups resulted in self-assembled carboxylate monolayers on the surface of TiO(2) which evolved into a uniform few-layered amorphous carbon coating during carbonizing at 750 °C. The product derived from the mixture of c-TiO(2) and citric acid with a mass ratio of 1 : 0.3 exhibits the optimal performance, revealing a high specific capacity (256.6 mA h g(−1) after 50 cycles at 0.1 A g(−1)) and outstanding cycling stability (retaining a capacity of 160.0 mA h g(−1) after 1000 cycles at 0.5 A g(−1)). The greatly enhanced capacity and cyclability correlate with the uniform few-layered carbon coating which not only ameliorates the electronic conductivity of c-TiO(2) but also avoids the reduction in ionic conductivity caused by thick carbon layers and redundant carbon.