Li2C2, a High‐Capacity Cathode Material for Lithium Ion Batteries. Issue 2 (26th November 2015) - Tian, Na
Abstract: As a typical alkaline earth metal carbide, lithium carbide (Li2 C2 ) has the highest theoretical specific capacity (1400 mA h g −1 ) among all the reported lithium‐containing cathode materials for lithium ion batteries. Herein, the feasibility of using Li2 C2 as a cathode material was studied. The results show that at least half of the lithium can be extracted from Li2 C2 and the reversible specific capacity reaches 700 mA h g −1 . The CC bond tends to rotate to form C4 (CC⋅⋅⋅CC) chains during lithium extraction, as indicated with the first‐principles molecular dynamics (FPMD) simulation. The low electronic and ionic conductivity are believed to be responsible for the potential gap between charge and discharge, as is supported with density functional theory (DFT) calculations and Arrhenius fitting results. These findings illustrate the feasibility to use the alkali and alkaline earth metal carbides as high‐capacity electrode materials for secondary batteries. Abstract : Lithium carbide (Li2 C2 ) is shown to function as a potential cathode material for lithium ion batteries. At least half of the lithium can be extracted and reinserted in Li2 C2 during cycling. These results open the door to future applications of alkali and alkaline earth metal electrodes.