Preparation and properties of MnF3 cathode materials for high-voltage thermal batteries

Abstract

• Single-phase MnF 3 were prepared by high-temperature fluorination. • High-conductivity CNTs were incorporated by high-energy ball milling. • At 110 mA cm −2 , the CNTs/MnF3 single cell exhibited high voltage of 3.46 V. • The thermal battery maintains a cell voltage above 1.5 V at 4.4 A cm −2 . Metal fluoride is considered an ideal cathode material for high-voltage thermal batteries. Herein, single-phase MnF 3 were prepared by high-temperature fluorination and incorporated high-conductivity carbon nanotubes (CNTs) by high-energy activated ball milling. At a current density of 110 mA cm −2 , the CNTs/MnF 3 single cell exhibited the cell voltage as high as 3.46 V, far exceeding others reported in the past. Moreover, it exhibits a short activation time of 0.66 s and maintains a cell voltage above 1.5 V at a high current density of 4.4 A cm −2 . This work presents an effective cathode material for thermal battery with high cell voltage and long working time.