The first charge and discharge capacities of cathode, at C between V, are mAh g−1 and mAh g −1 , respectively. The has excellent cycle stability with of capacity retention over 50 cycles. The coulombic efficiency of material is approximately 90% after 70 cycles. It is suggested that the structure of is stable during cycling and can be a promising cathode material for sodium ion batteries. | Communications in Physics, Vol. 27, No. 2 (2017), pp. 143-149 DOI: ELECTROCHEMICAL PERFORMANCE OF MnO2 SYNTHESIZED BY HYDROTHERMAL METHOD USING AS A CATHODE MATERIAL FOR SODIUM ION BATTERIES TAN ANH TA1 , LONG DUY PHAM2 , HIEU SY NGUYEN2 , CHUNG VU HOANG2 , CHI HA LE2 , CHIEN TRAN DANG3 , HOA THI THU NGUYEN4 AND NGHIA VAN NGUYEN4,† 1 Hanoi College of Education 2 Institute of Materials Science, Vietnam Academy of Science and Technology 3 Hanoi University of Natural Resources and Environment 4 Hanoi Architectural University † E-mail: Received 07 April 2017 Accepted for publication 14 June 2017 Published 30 June 2017 Abstract. Orthorhombic MnO2 with an S-shape tunnel structure was successfully synthesized by a hydrothermal method. The MnO2 material has lattice parameters of a = ˚ b = A, ˚ and c = A. ˚ Scanning electron microscope analysis reveals that the morA, phologies of MnO2 consist of MnO2 nanowires with diameters of about 30-50 nm and MnO2 particles with the size in the range of 200 to 500 nm. The first charge and discharge capacities of MnO2 cathode, at C between V, are mAh g−1 and mAh g−1 , respectively. The MnO2 has excellent cycle stability with of capacity retention over 50 cycles. The coulombic efficiency of MnO2 material is approximately 90% after 70 cycles. It is suggested that the structure of MnO2 is stable during cycling and MnO2 can be a promising cathode material for sodium ion batteries. Keywords: cathode materials, hydrothermal method, MnO2 , sodium ion battery. Classification numbers: , . c 2017 Vietnam Academy of Science and Technology 144 ELECTROCHEMICAL PERFORMANCE OF MnO2 SYNTHESIZED . I. INTRODUCTION Lithium ion batteries (LIBs) have been widely used in many fields such as electronic vehicles, portable electronic devices, .
