Core–Shell Aluminum@Carbon Nanospheres for Dual‐Ion Batteries with Excellent Cycling Performance under High Rates

Abstract Dual‐ion battery (DIB) has been proposed as a novel energy storage device with the merits of high safety, low cost and environmental friendliness. Herein, we have developed core/shell aluminum@carbon nanospheres (nAl@C) as anode material for DIB. The nanoscale framework is composed of an Al nanosphere and an amorphous carbon outer layer that is conductive and protective, facilitating the formation of a stable SEI film during cycling. Owing to the core‐shell structural design, the nAl@C nanospheres demonstrate significantly enhanced electrochemical performance in a nAl@C‐graphite DIB. The DIB exhibites high rate performance as well as superior cycling stability with a capacity of 88 mA h g ‐1 with 94.6% capacity retention and high Coulombic efficiency (> 99.5%) after 1000 cycles at a high current rate of 15 C. In addition, the nAl@C‐G DIB deliveres an ultrahigh specific energy of 148 W h kg ‐1 at a high power density of 3701 W kg ‐1 , which is much better than most commercial lithium‐ion batteries.