Alleviation of concentration polarization using density-controlled duplex electrode architecture to improve quick-charging performance of lithium-ion batteries

Abstract

A duplex electrode architecture (double-layer electrode, DLE) is constructed to alleviate concentration polarization during the lithiation of the negative electrode. A smaller local voltage deviation in the electrode after lithiation and a reduced probability of Li plating on the top surface of the electrode during high-current-density applications are benefits of the modulated tortuosity and porosity of the upper electrode layer. By reducing the Li-ion concentration polarization in the DLE, the delivered capacity at the C-rate charging step is significantly increased; consequently, the quick charge cycleability is improved. The electrode thickness after cycling and the degree of failure of the electrode due to Li plating and polarization growth were reduced by the uniform utilization of the active materials in the DLE. Given the alleviated concentration polarization after lithiation, the DLE structure exhibited promising electrochemical characteristics that significantly improved its quick-charging performance.