Amorphous FePO4/Carbon Nanotube Cathode Preparation via in Situ Nanoprecipitation and Coagulation in a Microreactor

摘要

In this article, nanostructured amorphous FePO4 (a-FePO4)–carbon nanotube (CNT) composites, with high purity of FePO4 and a controllable FePO4/C ratio, were directly synthesized by a fast nanoprecipitation process in a microreactor, using Fe(NO3)3 and (NH4)3PO4 as precursors. Oxidized CNTs are well dispersed via strong electrostatic repulsion in a high pH solution system. Subsequently, a-FePO4 nanoparticles are adhered onto CNTs just following the fast nanoprecipitation process; then, the precipitated composites are compacted by ball-milling, forming a compact conductive network with well dispersed and highly loaded active materials. As cathode materials for lithium-ion batteries, the composites exhibit a capacity of 175.8 mAh g–1 at 0.1 C, close to the theoretical capacity (178 mAh g–1), and a good cycle performance with a reversible capacity of 137.0 mAh g–1 after 500 cycles at 5 C. Importantly, the enhanced micromixing enables fast nanoprecipitation in suspension and opens a shortcut for constructing nanostructured composites that have potential in functionalization and are easy to handle.