Constructing carbon-decorated CFx nanocapsule by atomic layer deposition and catalytic chemical vapor deposition for high-capacity lithium primary battery

Abstract

Practical application of lithium/fluorinated carbon (Li/CFx) primary batteries in large powered devices is hindered due to the hindered delivery of its inherent capacity as a consequence of sluggish kinetics of electrode reaction and the large polarization due to poor conductivity of fluorinated carbon (CFx) in the case of a high F/C ratio. Herein, to improve the capacity performance, fluorinated carbon capsule (FCC) was decorated with conductive carbon layers by employing a combined atomic layer deposition and catalytic chemical vapor deposition (ALD-CCVD) technique. These precisely constructed carbon layers on the CFx surface maintained the original C–F bond types of FCC with a similar fluorination degree, indicating that the proposed method for capacity enhancement is effective and non-destructive. In comparison to raw FCC, the specific capacity of designed FCC@C increased up to 117.9% and 151.1% at the current densities of 0.01 A g−1 and 0.5 A g−1, respectively. The enhanced electrochemical performance is predominantly derived from the synergistic effect of FCC and conductive carbon layers, which further increases the electronic conductivity, specific surface area and the number of active sites for improving Li+ diffusion. This work puts forward an effective ALD-CCVD technique to enhance the capacity performance of lithium primary batteries.