High‐Rate Performance of Fluorinated Carbon Material Doped by Phosphorus Species for Lithium‐Fluorinated Carbon Battery

Abstract

The lithium–fluorinated carbon (Li/CFx) battery possesses the highest energy density (2180 Wh kg−1) among all the primary lithium batteries. However, the poor electronic conductivity of the fluorinated carbon (CFx) material sets a limit on its rate discharge capability, confining its practical application. In this article, a doping strategy at a mild anneal condition is developed to synthesize the phosphorus species‐doped CFx materials (P‐CFx) for Li/CFx batteries. Compared to the commonly used methods, this eco‐friendly, and simple doping method does not involve washing, centrifugation, and filtration processes. Characterization using X‐Ray diffraction, high‐resolution transmission electron microscope, and X‐Ray photoelectron spectroscopy confirms the successful doping and the structure of the P‐CFx. Density functional theory calculations and characterization results demonstrate that phosphorus species doping can alter microstructure and induce charge redistribution to improve electronic and ionic conductivity. Therefore, the Li/P‐CFx battery possesses a high specific capacity and an excellent rate capability, shown by a high discharge capacity of 810 mAh g−1 with a voltage plateau of 2.53 V at 0.1 C. Extraordinarily, a discharge capacity of 597 mAh g−1 with a voltage plateau of 1.90 V at 20 C has been achieved as well as a high power density of 34 048 W kg−1.

Phosphorus-Doped FeOF Nanoparticle-Based Cathodes for Lithium Storage

“…In comparison, the P-F6 displays a higher specific capacity of 551.4 mA h g −1 than FeOF of 521.1 mA h g −1 , which demonstrates that P doping can enhance the Li + transport kinetics. 47,48 Compared with pure FeOF, no new peaks can be found in the CV curve, indicating that the P atom did not participate in the electrochemical reaction. The P-F6 electrode achieved superior rate performance (Figure 4f) of 306.8, 259.9, 239.3, 196.5, 169.9, 147.9, and 104.8 mA h g −1 at 20 mA g −1 to 1000 mA g −1 .…”

Surface Engineering of Fluorinated Graphene Nanosheets Enables Ultrafast Lithium/Sodium/Potassium Primary Batteries

“…By defluorination, the bandgap of DFG is narrowed, and the Fermi energy falls in it, exhibiting metallic or semi‐metallic characteristics. [ 52 ] That is, the surface defluorination strategy significantly improves the conductivity and ion transport properties of DFG. The metallic‐like features of DFG‐N are further enhanced by simultaneous defluorination and nitrogen doping, as indicated by the high DOS at the Fermi level.…”

Fundamentals of Li/CFxbattery design and application

“…Zhu et al synthesised a P-doped fluorinated carbon (P-CF x ) material using phytic acid at 240 1C, the P-CF x material delivered a discharge capacity of 597 mA h g À1 at 20 C with a high-voltage plateau of 1.9 V and high power density of 34 048 W kg À1 . 193 In addition, heteroatoms, such as oxidised groups, can undergo self-discharging, which improves the battery performance. 194 Mar et al oxidised sub-fluorinated graphite, and the energy density of the oxidised sub-fluorinated graphite was considerably higher than that of sub-fluorinated graphite.…”

“…Zhu et al synthesised a P-doped fluorinated carbon (P-CF x ) material using phytic acid at 240 °C, the P-CF x material delivered a discharge capacity of 597 mA h g −1 at 20 C with a high-voltage plateau of 1.9 V and high power density of 34 048 W kg −1 . 193…”