Na-Ion Anode Based on Na(Li,Ti)O2 System: Effects of Mg Addition

  • Kim, Soo Hwa ;
  • Bae, Dong-Sik ;
  • Kim, Chang-Sam ;
  • Lee, June Gunn
  • Received : 2016.03.02
  • Accepted : 2016.05.18
  • Published : 2016.05.31


This study involves enhancing the performance of the $Na(Li,Ti)O_2$ system as an Na-ion battery anode with the addition of Mg, which partially replaces Li ions. We perform both computational and experimental approaches to achieve a higher reversible capacity and a faster transport of Na ions for the devised system. Computational results indicate that the $Na(Li,Mg,Ti)O_2$ system can provide a lower-barrier path for Na-ion diffusion than can a system without the addition of Mg. Experimentally, we synthesize various $Na_z(Li_y,Mg_x,Ti)O_2$ systems and evaluate their electrochemical characteristics. In agreement with the theoretical study, Mg addition to such systems improves general cell performance. For example, the prepared $Na_{0.646}(Li_{0.207}Mg_{0.013}Ti_{0.78})O_2$ system displays an increase in reversible capacity of 8.5% and in rate performance of 13.5%, compared to those characteristics of a system without the addition of Mg. Computational results indicate that these improvements can be attributed to the slight widening of the Na-$O_6$ layer in the presence of Mg in the $(Li,Ti)O_6$ layer.


Sodium-ion battery;P2 phase;Mg substitution;DFT;Barrier energy


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