Rechargeable li-ion batteries have been considered as a promising power source for the electric vehicles and the grid energy storage systems. However, lithium resources are limited and will restrict the huge applications of li-ion batteries. It is of great significance to develop eco-friendly sodium ion batteries which employ abundant sodium resources. Recently, we developed the large-scale synthesis route of NaNi1/3Fe1/3Mn1/3O2 (NFM) by using hydroxide co-precipitation combined with solid-state reaction, and the optimization reaction condition was studied by using in situ XRD. The metastable structure change of NaNi1/3Fe1/3Mn1/3O2 during electrochemical sodium ion intercalation which cycled at 0.1C rate between 2.0 to 4.0V, and 2.0 to 4.3V, were studied by using in operando TXM-XANES and XRD, and the thermal decomposition behavior and structure evolution of charged NaNi1/3Fe1/3Mn1/3O2 cathode material during heating process was measured by using in situ high-energy X-ray diffraction (HEXRD) technique.
The effect of Ca-substitution in Na sites on the structural and electrochemical properties of Na1-xCax/2NFM (x=0, 0.05, 0.1). X-ray diffraction patterns of the prepared Na1-xCax/2NFM samples show single α-NaFeO2 type phase with slightly increased alkali-layer distance as Ca content increased. The cycling stabilities of Ca-substituted samples are remarkably improved. The Na0.9Ca0.05NFM cathode delivers capacity of 116.3 mAh g-1 with capacity retention of 92% after 200 cycles at the 1C rate. In operando XRD indicates a reversible structural evolution through an O3-P3-P3-O3 sequence of the Na0.9Ca0.05NFM cathode during cycling. Compared to NaNMF, the Na0.9Ca0.05NFM cathode shows wider voltage range in pure P3 phase state during charge/discharge process and exhibits better structure recoverability after cycling. The superior cycling stability of Na0.9Ca0.05NFM makes it a promising material for practical applications in sodium ion batteries. A new portable energy storage device based on SIB has been designed and assembled. Layered oxide NaNi1/3Fe1/3Mn1/3O2 and hard carbon were used as cathode and anode, respectively. The SIB pouch cell has been designed and the electrochemistry and safety performance were tested.
 Y Xie, H. Wang, G. Xu et. al., Adv. Energy Mater., 2016,6(24) 1601306
 H Wang, X.-Z Liao, Y Yang et. al., J.Electrochem. Soc., 163 (2016) A565-A570.
 H Wang, X.-Z Liao, Y Xie, et. al., Energy Storage Science and Technology，2016, 5(1):65-68.
 H Wang, et. al., Electrochim. Acta, 113(2013)200-204
 D. Yang, et. al., J. Mater. Chem. A, 2(2014)6723-6726; 1(2013)13417-13421
 D. Yang, et. al., Chem. Commun., 50(2014)13377-13380; 51(2015) 8181- 8184.
 H.Che, S. Chen, Y. Xie, et al., Energy Environ. Sci., 10(2017) 1075-1101
 H.Che, J. Liu, H. Wang et al., Electrochem. Commun. 2017, 83(2017) 20-23.
 Y Yang, X.Yan, C. Ma, et al., J. Electrochem. Soc., 163 (2016) A2117-A2123
 L. Sun, Y. Xie, X,-Z. Liao, et al., Small，2018, 1701523