Pseudocapacitive trimetallic NiCoMn-111 perovskite fluorides for advanced Li-ion supercabatteries.

Exploring advanced electrochemical energy storage systems and clarifying their charge storage mechanisms are key scientific frontiers presenting a great challenge. Herein, we demonstrate a novel concept of Li-ion supercabatteries ( i.e. , Li-ion capacitors/batteries, LICBs), which were realized using a novel trimetallic Ni-Co-Mn perovskite fluoride (K 0.97 Ni 0.31 Co 0.34 Mn 0.35 F 2.98 , denoted as KNCMF-111 (8 # )) anode and a high-performance activated carbon/LiFePO 4 (AC/LFP) cathode, which makes the boundary between LICs and LIBs less distinctive. Thanks to the pseudocapacitive conversion mechanism of the KNCMF-111 (8 # ) anode with superior kinetics and the enhanced capacity of the capacitor/battery hybrid AC/LFP cathode, the designed KNCMF-111 (8 # )//AC/LFP LICBs, integrating the synergistic superiority of pseudocapacitive, capacitive and faradaic characteristics, exhibit remarkable energy/power densities and a long cycle life, indicating a high-efficiency energy storage application. Overall, this work provides new insights into exploring advanced Li-ion supercabatteries and clarifying their charge storage mechanisms based on trimetallic Ni-Co-Mn perovskite fluoride electrode materials, which sheds light on the development of advanced electrochemical energy storage systems and in-depth understanding of their charge storage mechanisms.