Voltage Control of Multiple Electrochemical Processes during Lithium Ion Migration in NiFeO Ferrite.

Li-ion-based electric field control has been attracting significant attention, since it is able to penetrate deep into materials to exhibit diverse and controllable electrochemical processes, which offer more degrees of freedom to design multifunctional devices with low power consumption. As opposed to previous studies that mainly focused on single lithiation/delithiation mechanisms, we reveal three Li-ion modulation mechanisms in the same NiFeO spinel ferrite by magnetometry, ., intercalation, conversion, and space charge, which are respectively demonstrated in high, medium, and low voltage range.

Reinterpreting the Intercalation-Conversion Mechanism of FeP Anodes in Lithium/Sodium-Ion Batteries from Evolution of the Magnetic Phase.

Batteries with intercalation-conversion-type electrodes tend to achieve high-capacity storage, but the complicated reaction process often suffers from confusing electrochemical mechanisms. Here, we reinterpreted the essential issue about the potential of the conversion reaction and whether there is an intercalation reaction in a lithium/sodium-ion battery (LIB/SIB) with the FeP anode based on the evolution of the magnetic phase. Especially, the ever-present intercalation process in a large voltage range followed by the conversion reaction with extremely low potential was confirmed in FeP LIB, while it is mainly the conversion reaction for the sodium storage mechanism in FeP SIB.