For its application within the FIBs as a potential cathode material, an attempt was made to determine the cycling stability of the parent RP phase. To do so, we examined cell reversibility on charging and discharging the cell to cutoff conditions of either 40 mAh g -1 or potentials of 1.3 V and 0 V against Pb/PbF2 on charging / discharging respectively. The capacity conditions were chosen according to the findings reported in section 3.1, which show increased amount of side reactions, if charging proceeds above 40 mAh g -1 . As seen from Figure , it is observed that the discharge capacity increases within the first 6 cycles after charging to the cutoff capacity of 40 mAh g -1 . This enhanced discharge capacity as a function of cycle number can be related to reduced side reactions of the carbon additives on increased cycling . Thus, as the cycle number increases, this leads to higher active material utilization i.e. intercalation of F -within the RP phase as opposed to the side reactions, thus leading to higher discharge capacities. In previous studies, La2NiO4 was cycled at the cut-off capacity of 30 mAh g -1 , whereas La2Ni0.75Co0.25O4.08 has shown certain stability at the increased cut off the capacity of 40 mAh g -1 and shows the cycling stability upto 120 cycles. Already after the first cycle (see Figure a), the charging plateau shifted from lower potential to high potential by about 0.3 V and the specific capacity increased by ~11 %. After the second cycle, the charging plateau shifted again by ~ +0.2 V together with a further increase of the specific capacity of 32 %. After this, the curves only show minor changes regarding their general shape up to 120 cycles (apart from a continuous increase of discharge capacity by 0.2 -0.3 mAh g -1 per cycle, see Figure 3, resulting in improved coulombic efficiency). The discharge capacity remains highly stable with the columbic efficiency of around 90 % without significant capacity fading for 120 cycles as shown in Figure b. La2NiO4 reported previously was found to show higher columbic efficiencies between 95-99% . The lower coulumbic efficiency of La2Ni0.75Co0.25O4.08 of up to 90% is thus likely related to consumptive processes at low cycles, and Co seems to be the most plausible origin for introducing the side reactions to the carbon additive. However, the capacity retention is also superior in comparison to pure La2CoO4 . In contrast to this, Co can also have beneficial influences on the cycling behavior. This was observed when cycling the material close to the theoretical cut-off capacity of 130mAh g -1 .