Achieving Desirable Initial Coulombic Efficiencies and Full Capacity Utilization of Li-Ion Batteries by Chemical Prelithiation of Graphite Anode

摘要

Chemical prelithiation is an effective approach to elevate the initial Coulombic efficiency (ICE) and energy utilization of Li-ion battery electrodes. However, this approach fails to operate for the most commonly used graphite (Gr) anode, because all the prelithiation reagents reported so far have a much higher redox potential than Gr (approximate to 0.2 V). Based on ionic solvation and coordination chemistry, for the first time, a new design strategy is proposed for prelithiation solution by selecting a strong electron-donating, sterically hindered, and chemically stable solvent to tune the redox potential of prelithiation reagent and also to prevent the solvent co-intercalation during prelithiation process, thus enabling a successful prelithiation of Gr anodes. By theoretical prediction and experimental evaluation, a chemical prelithiation solution, lithium biphenylide/2-methyl tetrahydrofuran, is successfully developed, which can prelithiate Gr anodes accurately to a desired state in few minutes without destroying the lattice structure of Gr. When the prelithiated Gr anodes (pGr) are paired with the conventional cathodes, the full cells demonstrate significantly improved ICEs and higher energy densities than their counterparts using pristine Gr anodes, showing a great prospect for wide Li-ion battery applications.