Layered potassium-deficient P2- and P3-type cathode materials KxMnO2 for K-ion batteries

An Exploratory Investigation of Spinel LiMn1.5Ni0.5O4 as Cathode Material for Potassium‐Ion Battery

“…The reversible capacity value of 90 mAh g À 1 displayed by KMNO is comparable to the values of~100 mAh g À 1 usually reported for layered manganese oxides investigated as cathode materials for KIBs. [14][15][16][17][18][19][20][21] Interestingly, the mid-discharge potential value of~3.10 V is~0.3 V higher than that observed for λ-MO. The consecutive charge is nearly symmetric, showing a wide sloping region followed by a quasi-voltage plateau at 4.40 V. A good efficiency of the potassium extraction/insertion reaction is observed for this second cycle.…”

“…Up until now, very few promising KIB cathode materials have been successfully reported. Three main categories of compounds have been explored: polyanionic compounds such as KVPO 4 F [10] and K 3 V 2 (PO 4 ) 3 , [11] hexacyanometalates such as Prussian blue KFe 2 (CN) 6 , [12] Prussian blue analogs [13] and layered oxides such as K 0.3 MnO 2 , [14,15] K 0.45 MnO 2 , [15] K 0.5 MnO 2 , [16] K 0.7 Fe 0.5 Mn 0.5 O 2 nanowires, [17] K 0.45 Mg 0.1 Mn 0.9 O 2 , [18] K 0.5 Ni 0.1 Mn 0.9 O 2 , [19] K 0.67 Mn 0.83 Ni 0.17 O 2 , [20] K 0.54 Co 0.5 Mn 0.5 O 2 , [21] K x CoO 2 , [22,23] K 0.5 V 2 O 5 [24] or Na 0.9 Cr 0.9 Ru 0.1 O 2 . [25] Specific capacities between 90-120 mAh g À 1 have been reported for Mn-based layered oxides, depending on the structure, the chemical composition and the voltage range.…”

“…[25] Specific capacities between 90-120 mAh g À 1 have been reported for Mn-based layered oxides, depending on the structure, the chemical composition and the voltage range. [14][15][16][17][18][19][20][21] An outstanding discharge capacity of 178 mAh g À 1 is achieved for K 0.7 Fe 0.5 Mn 0.5 O 2 nanowires, due to the contribution of the two redox systems Fe 4 + /Fe 3 + and Mn 4 + /Mn 3 + , even when the nature of the mechanism is not discussed. [17] Besides these cathode materials, a compound of interest is the 3D phase λ-MnO 2 (λ-MO) with the spinel structure, first isolated by Hunter et al [26] While previous studies have investigated the sodium insertion properties into chemically [27] or electrochemically prepared λ-MO, [28] potassium insertion in such spinel framework has not been reported yet.…”

Potassium Pre-Inserted K1.04Mn8O16 Cathode Materials for Aqueous Li-Ion and Na-Ion Hybrid Capacitors

“…The other one peak at 530.2 eV is in connection with Mn-OH. As a consequence, according to the above results, micro-sized KMO particles consist with nanoparticles and nanorods can be successfully achieved through facile high-temperature calcination36 .…”

Mosaic Red Phosphorus/MoS2 Hybrid as an Anode to Boost Potassium‐Ion Storage

“…Unfortunately, some demerits such as the inferior electrical conductivity, large polarization, and drastic volume expansion still impede the commercial application of KIBs. Hence, a diversity of innovations are being attempted to boost the K + storage capability of RP, such as fabricating black phosphorus, [3] making RP particles embed in graphite matrix, [4] confining phosphorus in mesoporous carbon skeleton, [5] forming various metallic phosphides (Sn 4 P 3 /C, [6] GeP 5 , [7] and CoP [8] et al), combining RP with diverse carbonaceous materials (graphite, [4] CNTs, [5] mesoporous carbon [9] and activated carbon [10] et al) and constructing various architectures (such as core-shell, [8] tubular [11] and layered [12] structure). For example, Wu et al [13] obtained a phosphorus/carbon composite by a simple ballmilling method which showed a much higher capacity with 323.5 mAh g À 1 after 50 cycles at a current density of 50 mA g À 1 in KIBs.…”