Structural transformation and electrochemical properties of a nanosized flower-like R-MnO2 cathode in a sodium battery

文献情報

出版日 2021-11-23

DOI 10.1039/D1CP04047B

インパクトファクター 3.676

著者

Kai Qiu, Mingxia Yan, Shouwang Zhao, Hongwei Fan, Shengli An, Xinping Qiu, Guixiao Jia

原文を見る

要旨

High-energy density and low-cost sodium–ion batteries are being sought to meet increasing energy demand. Here, R-MnO2 is chosen as a cathode material of sodium–ion batteries owing to its low cost and high energy density. The structural transformation from the tunnel R-MnO2 to the layered NaMnO2 and electrochemical properties during the charge/discharge are investigated at the atomic level by combining XRD and related electrochemical experiments. Na≤0.04MnO2 has a tunnel R-MnO2 phase structure, Na≥0.42MnO2 has a layered NaMnO2 phase structure, and Na0.04−0.42MnO2 is their mixed phase. Mn3+ 3d4[t2gβ3dz2(1)3dx2−y2(0)] in NaMnO2 loses one 3dz2 electron and the redox couple Mn3+/Mn4+ delivers 206 mA h g−1 during the initial charge. The case that the Fermi energy level difference between R-MnO2 and NaMnO2 is lower than that between the layered Na(12-x)/12MnO2 and NaMnO2 makes the potential plateau of R-MnO2 turning into NaMnO2 lower than that of the layered Na(12−x)/12MnO2 to NaMnO2. This can be confirmed by our experiment from the 1st–2nd voltage capacity profile of R-MnO2 in EC/PC (ethylene carbonate/propylene carbonate) electrolyte. The study would give a new view of the production of sustainable sodium battery cathode materials.

掲載誌

Physical Chemistry Chemical Physics

CiteScore: 5.5

自己引用率: 10.3%

年間論文数: 3036

Physical Chemistry Chemical Physics (PCCP) is an international journal co-owned by 19 physical chemistry and physics societies from around the world. This journal publishes original, cutting-edge research in physical chemistry, chemical physics and biophysical chemistry. To be suitable for publication in PCCP, articles must include significant innovation and/or insight into physical chemistry; this is the most important criterion that reviewers and Editors will judge against when evaluating submissions. The journal has a broad scope and welcomes contributions spanning experiment, theory, computation and data science. Topical coverage includes spectroscopy, dynamics, kinetics, statistical mechanics, thermodynamics, electrochemistry, catalysis, surface science, quantum mechanics, quantum computing and machine learning. Interdisciplinary research areas such as polymers and soft matter, materials, nanoscience, energy, surfaces/interfaces, and biophysical chemistry are welcomed if they demonstrate significant innovation and/or insight into physical chemistry. Joined experimental/theoretical studies are particularly appreciated when complementary and based on up-to-date approaches.