Aluminum Manganese Oxides with Mixed Crystal Structure: High-Energy-Density Cathodes for Rechargeable Sodium Batteries

Authors

  • Dr. Dong-Wook Han,

    Corresponding author
    1. Energy Storage Group, Samsung Advanced Institute of Technology (SAIT), Samsung Electronics Co., Ltd. Yongin 446-712 (Korea)
    • Energy Storage Group, Samsung Advanced Institute of Technology (SAIT), Samsung Electronics Co., Ltd. Yongin 446-712 (Korea)===

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  • Jun-Hwan Ku,

    1. Energy Storage Group, Samsung Advanced Institute of Technology (SAIT), Samsung Electronics Co., Ltd. Yongin 446-712 (Korea)
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  • Ryoung-Hee Kim,

    1. Energy Storage Group, Samsung Advanced Institute of Technology (SAIT), Samsung Electronics Co., Ltd. Yongin 446-712 (Korea)
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  • Dr. Dong-Jin Yun,

    1. Analytical Science Laboratory, Samsung Advanced Institute of Technology (SAIT), Samsung Electronics Co., Ltd. Yongin 446-712 (Korea)
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  • Seok-Soo Lee,

    Corresponding author
    1. Energy Storage Group, Samsung Advanced Institute of Technology (SAIT), Samsung Electronics Co., Ltd. Yongin 446-712 (Korea)
    • Energy Storage Group, Samsung Advanced Institute of Technology (SAIT), Samsung Electronics Co., Ltd. Yongin 446-712 (Korea)===

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  • Seok-Gwang Doo

    1. Energy Storage Group, Samsung Advanced Institute of Technology (SAIT), Samsung Electronics Co., Ltd. Yongin 446-712 (Korea)
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Abstract

We report a new discovery for enhancing the energy density of manganese oxide (NaxMnO2) cathode materials for sodium rechargeable batteries by incorporation of aluminum. The Al incorporation results in NaAl0.1Mn0.9O2 with a mixture of tunnel and layered crystal structures. NaAl0.1Mn0.9O2 shows a much higher initial discharge capacity and superior cycling performance compared to pristine Na0.65MnO2. We ascribe this enhancement in performance to the formation of a new orthorhombic layered NaMnO2 phase merged with a small amount of tunnel Na0.44MnO2 phase in NaAl0.1Mn0.9O2, and to improvements in the surface stability of the NaAl0.1Mn0.9O2 particles caused by the formation of Al[BOND]O bonds on their surfaces. Our findings regarding the phase transformation and structure stabilization induced by incorporation of aluminum, closely related to the structural analogy between orthorhombic Na0.44MnO2 and NaAl0.1Mn0.9O2, suggest a strategy for achieving sodium rechargeable batteries with high energy density and stability.

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