Simple fabrication of Ni nanodots decorated Ni/Ketjen black composite for sulfur host in lithium‐sulfur battery

Ni nanomaterials exhibit excellent adsorption and catalytic ability in the redox reaction of Li-S batteries. Hence, Ni nanodots are embedded in the micropores and mesopores of commercial Ketjen black (KB) to obtain Ni/KB composite nanomaterials by an in situ preparation method with low cost and high yield. The prepared Ni nanodots with 5 to 30 nm diameter act as the active sites in KB matrix and enhance the intrinsic activity; they can not only adsorb lithium polysulfides (LiPSs) by the Ni-S bond but also promote the conversion rate of LiPSs. Consequently, with 3.1 mg cm−2 S loading on positive electrode, the initial discharge capacity of Ni/KB/S electrode at 0.05 C reaches 1253 mAh g−1 and the initial discharge capacity at 0.5 C reaches 818.4 mAh g−1, with the stable cycle exceeding over 500 cycles.