A novel Li‐ion supercapattery by K‐ion vacant ternary perovskite fluoride anode with pseudocapacitive conversion/insertion dual mechanisms
Yongfa Huang, Rui Ding, Danfeng Ying, Yu‐Xi Huang, Tong Yan, Caini Tan, Xiujuan Sun, Enhui Liu
Abstract
Abstract An innovative K + vacant ternary perovskite fluoride (K 0.89 Ni 0.02 Co 0.03 Mn 0.95 F 3.0 , KNCMF‐3#) anode was designed for advanced Li‐ion supercapattery (i.e., Li‐ion capacitors/batteries, LIC/Bs). Owing to the conversion/insertion dual mechanisms and fast pseudocapacitive control dynamics, the KNCMF‐3# electrode exhibits superior electrochemical performance, especially the excellent cycle performance (467% (229 mAh·g −1 )/1000 cycles/2 A·g −1 ). Moreover, the hybrid KNCMF‐3#/reduced graphene oxide (rGO) electrode can further increase the electrochemical performance (217–97 mAh·g −1 /0.1–3.2 A·g −1 , 150% (197 mAh·g −1 )/1000 cycles/2 A·g −1 ). Also, a novel capacitor/battery cathode, activated carbon (AC) + LiFePO 4 + graphene (AC + LFP + G), exhibits impressive performance (128–82 mAh·g −1 /0.1–3.2 A·g −1 , 84%/1000 cycles/2 A·g −1 ). By the synergistic optimization of anode and cathode, the Li‐ion supercapattery KNCMF‐3#@rGO//AC + LFP + G demonstrates remarkable performance, for example, 111.9–23.8 Wh·kg −1 /0.4–8.0 kW·kg −1 /82%/2000 cycles/5 A·g −1 /0–4 V, which is superior to KNCMF‐3#//AC LICs, KNCMF‐3#@rGO//AC LICs, KNCMF‐3#//AC + LFP + G LIC/Bs. In all, the novel Li‐ion supercapattery idea adds a promising perspective to develop advanced energy storage devices.