Effect of Current Density on Specific Characteristics of Negative Electrodes for Lithium-Ion Batteries Based on Heat-Treated Petroleum Coke

Abstract

The results of comparative studies of the effect of current density on the average discharge voltage and specific discharge capacity of carbon electrodes based on heat-treated petroleum coke and graphite are presented. The carbon obtained by heat treatment of petroleum coke is shown to have better kinetic characteristics than graphite. The increase in the current density from 0.2 mA/cm2 (36 mA/g) to 2 mA/cm2 (364 mA/g) leads to a decrease in the discharge capacity of heat-treated petroleum coke by 26%; graphite, by 93%. When the current density is restored to 0.2 mA/cm2, the discharge capacity of carbon electrodes is also restored to its initial value. The increase in the current density is also shown to lead to increase in the average discharge voltage of lithium–carbon cells. Thus, with the increase in current density from 0.2 to 2 mA/cm2, the average discharge voltage of the lithium–carbon cells with the electrode active component of the heat-treated petroleum coke increased from 0.39 to 0.62 V; that of graphite, from 0.14 to 0.35 V.