Effect of Al-Doping on the Electrochemical Performances of O_3-Type Nanmc Cathode Material for Sodium-Ion Batteries

摘要

The emergence of Lithium-ion technology as a primary power source has revolutionized the global electric vehicle battery market, the high abundance, uniform geological distribution and similar electrochemistry of sodium, making sodium-ion batteries (NIBs) a promising LIB supplement in the large-scale energy storage applications. Layered sodium transition metal oxide of O_3-NaMO_2-type such as NaCoO_2, NaMnO_2, NaNiO_2, and NaFeO_2, etc. have been investigated to show reversible Na-ion insertion within the applied potential limit. They suffer from their characteristic disadvantages, such as low redox potential of NaCoO_2, complex phase transition of NaNiO_2, electrolyte dissolution of Mn~(+2) of NaMnO_2 and rapid capacity fading of NaFeO_2. Therefore, the strategy of cation mixing to develop the multi-metallic oxides has been explored well to utilize the synergistic effects of all metal ions. O_3-type layered NaNi_(0.5)Mn_(0.3)Co_(0.2)O_2 is considered as one of the most promising cathode materials for NIBs. O_3-NaNi_(0.5)Mn_(0.3)Co_(0.2)O_2 as cathode material for SIBs delivers a 1st cycle capacity of 135 mAh g~(-1) with the 37% capacity fade at the end of 200th cycle at C/10 current rate.