Effect of copper substitution on the electrochemical properties of high entropy layered oxides cathode materials for sodium-ion batteries

Enhanced Rate Performance and Available Specific Capacity of the O3-NaNi0.5Mn0.3Ti0.2O2 Cathode by K Substitution for Sodium-Ion Batteries

“…From the figure, we can see that the CV curves of all materials have the same characteristics, which implies that they have the same charging and discharging mechanisms. Two pairs of distinct redox peaks at 3.3/2.6 V and 4.2/4.0 V can be seen on the CV curves, in addition to two pairs of weaker redox peaks between 3.4 and 3.7 V. The redox peaks at 3.3/2.6 V may be the redox of Ni 2+ /Ni 3+ , and the redox peaks at 4.2/4.0 V may be the redox of Ni 3+ /Ni 4+ , , while the weak redox peak between 3.4 V and 3.7 V may be the order of Na + /vacancy. , The degree of polarization of these materials was studied by analyzing the redox peaks at 2.5–3.5 V; the degree of polarization Δo of NMT0 is 0.829 V, and it is 0.707 V for the KNMT50 sample, indicating that the polarization degree of the electrode materials decreases and the reversibility of redox increases after K doping. The CV curve of the KNMT50 material has the largest area, which implies that the KNMT50 material has a higher available specific capacity.…”

Recent progress in high-voltage P2-NaxTMO2 materials and their future perspectives

“…Recently, the method of building high entropy oxides has been proven to be another possible strategy to improve the performance of O3-layered oxide cathodes. [118][119][120][121][122] The use of high entropy P2-Na 0.6 (Ti 0.2 Mn 0.2 Co 0.2 Ni 0.2 Ru 0.2 )O 2 can tune the entropic stabilization of the crystal structure and the diffusion activation energy barriers, leading to superior rate performance at a very high rate (68 mA h g −1 at 86C). 123 This work demonstrated an advanced fast-charging layered oxide cathode for SIBs.…”

K2[(VOHPO4)2(C2O4)]·2H2O as a high‐potential cathode material for potassium‐ion batteries

“…[31][32][33][34][35] Among them, layered oxides possess the advantages of easy synthesis and high specific discharge capacity. 36 Several compounds, such as K 0.6 CoO 2 , 37 KCrO 2 , 38 K 0.65 Fe 0.5 Mn 0.5 O 2 , 39 and so on, have been reported in the literature. However, these compounds exhibit stepwise charge-discharge potential profiles with average discharge voltages often less than 2.5 V (vs. K + /K), leading to unsatisfactory specific energy for KIBs.…”

“…Presently, a limited array of materials have been assessed as cathode materials for KIBs, encompassing layered compounds, 22‐26 Prussian blue analogs, 11,27‐30 and polyanionic compounds 31‐35 . Among them, layered oxides possess the advantages of easy synthesis and high specific discharge capacity 36 . Several compounds, such as K 0.6 CoO 2 , 37 KCrO 2 , 38 K 0.65 Fe 0.5 Mn 0.5 O 2 , 39 and so on, have been reported in the literature.…”