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

Zhongyu Wang; Yangcheng Lu

doi:10.1021/acsomega.9b01343

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

ACS Omega. 2019 Sep 9;4(12):14790-14799. doi: 10.1021/acsomega.9b01343. eCollection 2019 Sep 17.

Authors

Zhongyu Wang¹, Yangcheng Lu¹

Affiliation

¹ State Key Laboratory of Chemical Engineering, Department of Chemical Engineering, Tsinghua University, Beijing 100084, China.

Abstract

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.