Magnetism vs. LiFePO4 battery´s state of charge: A route to a novel sensor concept

In recent years, LiFePO₄ has become a versatile cathode active material for rechargeable batteries. Unfortunately, the control of the battery´s state of charge is not uniquely determined by measuring just the LiFePO₄ battery´s open circuit voltage. For this reason, an alternative way of state of charge control is introduced by investigating the battery´s magnetic susceptibility. This is motivated by the change of the iron atoms´s magnetic state in the LiFePO₄ cathode material during charging and discharging. The magnetic susceptibility of differently oxidized LiFePO₄ samples will be investigated in order to correlate the magnetic sensitivity with the SOC in view of a new sensor concept.