Effects of oxidized Ketjen Black as conductive additives on electrochemical performance of the LiMn2O4@Al2O3 cathode in lithium-ion batteries

Abstract

Metal oxide modified LiMn2O4 (LMO) is an effective method to improve the cycling performance. However, the metal oxide usually has low electronic conductivity, which lead to poor rate performance. Herein, Al2O3 modified LMO (LMO@AO) with enough oxygen vacancies have been prepared, and further constructed a highly conductive network of LMO@AO/KBO electrode though a self-assembly method using oxidized Ketjen Black (KBO) as conductive carbon additives. The KBO with a large number of oxygen-containing groups and show a negative charge state, while LiMn2O4@Al2O3 particles have a positive charge state. Therefore, the KBO can uniformly adsorption on the surface of LMO@AO particles, forming a continuously conductive network by self-assembly process. In this constructed architecture, a continuously conductive network can not only enhance the electronic conductivity but also facilitate the Li ions transport. As a result, the LMO@AO/KBO-3 electrode still shows excellent rate capability (a high reversible capacity of 83.3 mAh g−1 can be achieved at ultrahigh rate of 10 C) and superior long-term cycling stability (with a high capacity retention of 85.2% at 10 C even after 900 cycles).