Pushing capacities and energy densities beyond theoretical limits of lithium primary batteries using active CF_x nanocapsules with x > 1

Abstract

The high theoretical capacity and long shelf-life of the Li-CFx system make it most promising for portable electronics. However, the inactivation ideology of -CF3 groups in CFx hinders the development...

Fluorinated Carbon Nanohorns as Cathode Materials for Ultra‐High Power Li/CFx Batteries

“…Although these groups contribute to the improvement of the specific capacity, they simultaneously reduce the electrochemical activity of the FCNH, causing ohmic polarization and reducing the discharge plateau. [ 37 ] The specific capacities of FCNH‐120, FCNH‐160, FCNH‐200, and FCNH‐240 are 748.5, 769.5, 775.2, and 863.4 mAh g −1 , respectively, at 0.05 C, which are slightly higher than the theoretical capacities based on their F/C ratios. These results indicate that almost all the C─F bonds are involved in the discharge reaction, and the extra capacity is attributed to Li + storage by the defective pore structure.…”

High Energy Density of Ball-Milled Fluorinated Carbon Nanofibers as Cathode in Primary Lithium Batteries

“…Ball milling, a simple process for reducing the particle size of a compound, is widely used for electrode materials [ 30 , 31 , 32 , 33 , 34 ], creating more space to accumulate the LiF(s) particles formed. Some milling treatments of fluorinated carbons under different conditions, with or without additives, have led to improved electrochemical performance [ 35 , 36 ]. The milling of CFx in the presence of urea has made it possible to reduce particle size and increase inter-layer spacing.…”

“…The use of nanometric fluorinated carbons has already produced good results in lithium batteries. Ahmad et al achieved a very high capacity of 1180 mAh/g by using fluorinated carbon nanodisks with both a low CF 2 and CF 3 group content and a ‘reinforcement’ effect by the core of the matrix (a few disks are maintained at the core of the matrix after electrochemical reduction); this makes it possible to achieve an ‘extracapacity’, i.e., a capacity greater than the theoretical one, involving a new electrochemical mechanism in addition to the one conventionally described [ 36 ]. Multi-walled fluorinated carbon nanotubes (F/C = 0.81) showed improved energy and power densities with 2007 Wh/kg and 3861 W/kg delivered in a lithium battery [ 37 ].…”