Additional Funding Sources
The project described was supported by the Pacific Northwest Louis Stokes Alliance for Minority Participation through the National Science Foundation under Award No. HRD-1410465. This research is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences program under Award No. DE-SC0019121.
Abstract
Lithium-ion batteries (LIBs) have been a popular option for many applications in electrical energy storage. However, concerns over the availability of lithium and cobalt, the two most common elements used in LIBs, have led to the renewed interest in more sustainable alternatives, especially in large-scale energy storage applications. Sodium-ion batteries (SIBs) have gained an interest as an alternative due to the large abundance of sodium and relatively low cost. In particular, layered transition metal oxides (LTMOs) have been the main focus of positive electrode materials research due to their high capacities, and high operating voltage. The P3-type Na0.5Ni0.25Mn0.75O2 material is a promising manganese-rich positive electrode for future SIBs due to its high working voltage and capacity. However, fast capacity fading due to the high voltage P3-O3 phase transition has been the bottleneck for commercialization of such materials. To combat this limitation, we attempted to synthesize a heterostructured P2-Na2/3MnO2-coated P3-Na0.5Ni0.25Mn0.75O2 cathode material. The created material exhibited an increased capacity of 119.3 mA h g-1 at 1C rate and improved cycling stability of 64.7% retention after 80 cycles at 1C. However, characterization techniques, including HR-TEM, SEM, and XRD, have not shown that the hypothesized layer has grown. Future research should be done into realizing the effect that our synthesis had upon the P3 material, and how to implement it towards the improvement of manganese-rich P3-type sodium LTMO cathode materials for future applications.
P2/P3 Heterostructured Layered Transition Metal Oxide Cathode Materials in Sodium-Ion Batteries
Lithium-ion batteries (LIBs) have been a popular option for many applications in electrical energy storage. However, concerns over the availability of lithium and cobalt, the two most common elements used in LIBs, have led to the renewed interest in more sustainable alternatives, especially in large-scale energy storage applications. Sodium-ion batteries (SIBs) have gained an interest as an alternative due to the large abundance of sodium and relatively low cost. In particular, layered transition metal oxides (LTMOs) have been the main focus of positive electrode materials research due to their high capacities, and high operating voltage. The P3-type Na0.5Ni0.25Mn0.75O2 material is a promising manganese-rich positive electrode for future SIBs due to its high working voltage and capacity. However, fast capacity fading due to the high voltage P3-O3 phase transition has been the bottleneck for commercialization of such materials. To combat this limitation, we attempted to synthesize a heterostructured P2-Na2/3MnO2-coated P3-Na0.5Ni0.25Mn0.75O2 cathode material. The created material exhibited an increased capacity of 119.3 mA h g-1 at 1C rate and improved cycling stability of 64.7% retention after 80 cycles at 1C. However, characterization techniques, including HR-TEM, SEM, and XRD, have not shown that the hypothesized layer has grown. Future research should be done into realizing the effect that our synthesis had upon the P3 material, and how to implement it towards the improvement of manganese-rich P3-type sodium LTMO cathode materials for future applications.