Thermally Activated P2‐O3 Mixed Layered Cathodes toward Synergistic Electrochemical Enhancement for Na Ion Batteries. Issue 44 (13th October 2021)

• Record Type: Journal Article
• Authors: Yang, Junghoon; Lim, Jin‐Myoung; Park, Mihui; Lee, Gi‐Hyeok; Lee, Suwon; Cho, Maenghyo; Kang, Yong‐Mook
• Is Part Of: Advanced energy materials. Volume 11:Issue 44(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-10-13
• Subjects: cathode materials -- phase formation -- sodium carbonate -- sodium ion batteries -- sodium manganese oxides -- thermal activation; Energy harvesting -- Materials -- Periodicals; Energy conversion -- Materials -- Periodicals; Energy storage -- Materials -- Periodicals; Photovoltaics -- Periodicals; Fuel cells -- Periodicals; Thermoelectric materials -- Periodicals; 621.31
• DOI: 10.1002/aenm.202102444
• Languages: English
• ISSNs: 1614-6832

Abstract

Abstract: Layer‐structured oxide cathodes have a lot of phases, which can be varied depending on Na ion contents and finally determine their electrochemical properties. Therefore, the off‐stoichiometry of layer‐structured oxides with the Na ions may differentiate not only their capacities but also the cyclic stabilities, kinetics, and so on, highlighting the importance of Na ion content. However, Na2 CO3 tends to be irreversibly formed on surface by making use of the Na ions lost from the lattice. Thereby, the O3 phase with stoichiometric Na content changes into the off‐stoichiometric P2 phase bringing about significant disadvantages. To address this issue, a thermal activation process is suggested to simultaneously decompose Na2 CO3 into electrochemically active Na ions and modulate the off‐stoichiometric P2 phase into the stoichiometric O3 phase. This study indicates that minimizing the loss of Na ions and maintaining the lattice framework with higher contents of Na ions during the synthesis of Na‐incorporating layered cathodes should be a key toward attaining electrochemical superiority. Abstract : Irreversible sodium carbonate formation induces off‐stoichiometry of layer‐structured oxides cathodes and poor electrochemical properties. A thermal activation process is proposed to simultaneously decompose sodium carbonate into electrochemically active sodium ions and improve electrochemical properties by the evolution of P2‐O3 hybrid lattice.