Synergistical heterointerface engineering of Fe‐Se nanocomposite for high‐performance sodium‐ion hybrid capacitors
Puguang Ji, Ying Liu, Shuangbin Han, Yufu Yan, О. В. Толочко, Eugene Strativnov, Mirtemir Shodievich Kurbanov, Hua Wang, Chengwei Zhang, Gongkai Wang
Abstract
Abstract As environmentally benign and high‐efficiency energy storage devices, sodium‐ion capacitors (SICs), which combine the merits of batteries and supercapacitors, are considered to have potentially high energy/power densities and long lifespan. However, the lack of high‐rate anodes that can match the high‐power‐density cathode hinders the commercial application of SICs. In this work, heterostructured Fe/FeSe 2 /Fe 3 Se 4 nanocomposite is prepared by chemical vapor deposition (CVD) method and investigated as the anode for SICs. Through heterointerface manipulation, Fe/FeSe 2 /Fe 3 Se 4 demonstrates better sodium ion storage performances than the pure FeSe 2 and FeSe 2 /Fe 3 Se 4 . It can deliver a specific capacity of 484.8 mAh·g −1 after 100 cycles at 0.5 A·g −1 , as well as a good capacity retention. The excellent performance of Fe/FeSe 2 /Fe 3 Se 4 nanocomposite can be ascribed to the synergistic effect of the heterointerface engineered components, where FeSe 2 and Fe 3 Se 4 are responsible for offering a high capacity and metallic Fe can server as mini‐current collectors, effectively accelerating the electron and charge transfer behavior. Meanwhile, the heterointerface significantly facilitates the sodium ion fast transport, and retards the structural variation during cycling. FeSe‐1000//activated carbon (AC) SIC affords a high energy density of 112 Wh·kg −1 at 107.5 W·kg −1 , its power density can achieve 10,750 W·kg −1 with remained energy density of 44.2 Wh·kg −1 , as well as an outstanding cycling stability, demonstrating this effective heterointerface engineered anode strategy for high‐performance SICs.