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.