A low-cost sulfur-loading material based on the modification of Ketjen Black for rechargeable lithium-sulfur battery

The practical application of lithium-sulfur (Li-S) battery is impeded by some technical hurdles such as short cycle life and poor capability, which is radically caused by the uncontrollable electrochemical reactions at the cathode. In this work, we develop a Ketjen Black carbon-based cathode material, modified with transition metals through the coordination fixing action of 2, 2′-bipyridine and followed with an annealing activation process, to be employed as the sulfur host in a Li-S battery. It is demonstrated that the decoration of Co and Fe on the matrix of carbon can substantially enhance the efficiency for catalytic conversion of polysulfides in Li-S batteries, thus greatly improving the performance, including capacity, rate capability and cycling life. This simple and economic strategy of modifying the commercial Ketjen Black shall accelerate the practical application of Li-S battery.