Tuning electronic structure of δ-MnO2 by the alkali-ion (K, Na, Li) associated manganese vacancies for high-rate supercapacitors

Emerging two-dimensional nanostructured manganese-based materials for electrochemical energy storage: recent advances, mechanisms, challenges, and prospects

“…Finally, compared to pure MnO 2 , the specific capacitances of optimized 0.4 KMO (K/Mn = 0.4), 0.4NaMO and 0.4LiMO samples are enhanced about 1.9, 1.6 and 1.6 times, respectively. 335 In early research, single-layer MnO 2 nanosheets with Mn vacancies can be synthesized by adjusting the temperature of precursors generated by the reaction. For example, when KMnO 4 is used to synthesize a precursor (K x MnO 2 ) with Mn vacancies, the lower the temperature, the more Mn vacancies there are.…”

Template and sol‐gel routed CoMn 2 O 4 nanofibers for supercapacitor applications

“…Furthermore, the diameter of the semicircle denotes the charge‐transfer resistance ( R ct ). One straight line further suggests the Warburg impedance of electrolytic ion diffusion in the prepared material 56 . It is notable that a very small increment in the EIS parameter occurs after 7000 charging/discharging cycles, further verifying the stability of the electrode material.…”

Ammonium nickel‐cobalt phosphate nanoflowers on highly conductive carbon fibers as an electrode material for enhanced electrochemical performance supercapacitors

“…The supercapacitor electrodes based on the above carbon materials have excellent electrochemical performances for an engineer application in high energy, high power, or low cost. However, it was reported that the non‐carbonaceous materials like transition metal hydroxides, oxides, sulfides, and phosphates (such as Co (OH) 2 , 17 MnO 2 , 18 NiO, 19 Co 3 O 4 , 20 CoS, 21 MnPO 4 , 22 and Co 3 (PO 4 ) 2 23 ) possess pseudocapacitance characteristics. Among various materials, transition metal phosphate has the advantages of a low cost, natural abundance, and excellent pseudocapacitive performance 24 .…”