Preparation of High‐Power Lithium Fluoride Carbon Battery via Microstructural Modulation of Ketjen Black

Abstract

Ketjen black fluoride (KBF‐2) material, a novel carbon fluoride cathode nanomaterial, is fabricated through a pregrinding treatment followed by a fluorination process for lithium primary batteries. The ketjen black material as the carbon precursors provides a 3D spherical structure with a high‐specific surface area. In addition, the pregrinding treatment results in several cracks in the spherical KBF‐2 particles. The effects of cracks on the fluorine content ratio under the same fluorination process conditions, diffusion coefficient of lithium ions, rate performance, and power density performance are investigated. At an extremely high current density of 4.5 A g−1(at a 6 C rate), the discharge capacity retention is 52.09%, which is a breakthrough for the series of fluoride cathode materials. Moreover, the KBF‐2 cathode is evaluated in a 10 Ah KBF‐2/Li primary pouch cell and demonstrated a high gravimetric energy density of 573.70 Wh kg−1 at a 0.5 C rate, and the discharge duration time reached 624 s under a constant specific power of 1,500 W kg−1. These factors contribute to the remarkable energy density performance and power output stability, particularly at high current densities.