The Effect of Organic Carbon Source on Performance of Liti(PO4)3/C Composite Electrodes in Aqueous Solutions

Abstract

The spherical LiTi(PO4)3/C composites were prepared through spray drying method followed high-temperature calcination and used as anodes for aqueous lithium ion batteries. The effect of different organic carbon source based on different coating mechanisms and carbon content on the electrochemical properties of LiTi(PO4)3/C composite anodes were investigated. Results show that the amount of carbon coating is too low to prevent water from eroding. In contrast, if the amount of carbon coating is too high, the resistance of lithium ion diffusion will be high; the optimal carbon coating amount of LiTi2(PO4)3/C electrodes is 13%. The uniformity of carbon coating and the thickness of coating layer are the two main factors affecting the performance of coated electrodes. The coating mechanism has critical influence on the uniformity of carbon coating. The most uniform carbon coating was obtained by using polydopamine as the carbon source, followed by using the organic macromolecule, glucose as the carbon source. Polyacrylonitrile containing both carbon and nitrogen exhibits no special effect of nitrogen doping. (The two main factors affecting the performance of the carbon coated electrode are the uniformity and the thickness of the carbon layer.) The best performance is achieved by LiTi2(PO4)3/C anodes with the carbon amount of 13% prepared by using polydopamine as the carbon source. But, from a viewpoint of mass production and scale-up, it is more suitable to use low-cost and water-soluble glucose as carbon source.