Synthesis of sodium manganese oxides with tailored multi-morphologies and their application in lithium/sodium ion batteries

Abstract

Sodium manganese oxides (SMO) with different crystal structures have been synthesized by high-temperature solid-state reaction (HTSSR), in which both morphology and crystal structure of SMO can be well-controlled by synergistic effects of both the ratio of sodium-to-manganese and the heat-treatment temperature. The material is further used as the cathode in Li/Na-ion batteries, and the experimental results indicated that the performance of SMO as the electrode material mainly depends on its crystal structure, while its morphology only plays an important role in the initial stage. SMO with a 3-D tunnel structure (Na_0.44MnO₂) and a layer structure (Na_0.67MnO₂ and Na_0.91MnO₂) delivers better battery performance.