Nanosilver‐Promoted Trimetallic Ni–Co–Mn Perovskite Fluorides for Advanced Aqueous Supercabatteries with Pseudocapacitive Multielectrons Phase Conversion Mechanisms

Abstract Aqueous supercapacitors (ASCs) and batteries (ABs) have drawn great attention as promising energy storage devices. However, the key issues of limited energy density of ASCs and inferior power density/poor cycling life of ABs discourage their further application. Herein, a new concept of advanced aqueous supercabatteries (ASCBs) realized by nanosilver‐promoted trimetallic Ni–Co–Mn perovskite fluorides (K 1.0 Ni 0.4 Co 0.2 Mn 0.4 F 3.2 (KNCMF‐10 # )/Ag(37%), denoted as 10 # /Ag(37%)) electrode materials is proposed, integrating with the respective superior specific power/cycling behavior and energy density of ASCs and ABs. A pseudocapacitance‐dominated multielectrons phase conversion mechanism of the 10 # /Ag(37%) electrode materials can be deduced by ex situ characterizations and electrochemical techniques. The constructed ASCBs by matching 10 # /Ag(37%) cathode with activated carbon (AC)/Bi(17%) anode achieve great energy density without sacrifice of power density and cycling life in wide temperatures, benefiting from the synergistic energy storage superiority of ASCs and ABs containing capacitive, pseudocapacitive, and Faradaic response in electrochemical processes. Overall, this work highlights the new idea of nano‐Ag‐promoted trimetallic Ni–Co–Mn perovskite fluorides with a pseudocapacitive multielectrons phase conversion mechanism as a new pop star for advanced ASCBs, showing a great significance in the context of designing advanced electrode materials and in‐depth understanding of their complicated charge storage mechanisms for aqueous electrochemical energy storage systems.