Currently, the development of the sodium-ion (Na-ion) batteries as an alternative to lithium-ion batteries has been accelerated to meet the energy demands of large-scale power applications. The difficulty of obtaining suitable electrode materials capable of storing large amount of Na-ion arises from the large radius of Na-ion that restricts its reversible capacity. Herein, Mn2O3 powders are synthesised through the thermal conversion of MnCO3 and reported for the first time as an anode for Na-ion batteries. The phase, morphology and charge/discharge characteristics of Mn2O3 obtained are evaluated systematically. The cubic-like Mn2O3 with particle sizes approximately 1.0–1.5 µm coupled with the formation of Mn2O3 sub-units on its surface create a positive effect on the insertion/deinsertion of Na-ion. Mn2O3 delivers a first discharge capacity of 544 mAh g−1 and retains its capacity by 85% after 200 cycles at 100 mA g−1, demonstrating the excellent cyclability of the Mn2O3 electrode. Therefore, this study provides a significant contribution towards exploring the potential of Mn2O3 as a promising anode in the development of Na-ion batteries.

The emerging sodium-ion (Na-ion) batteries have drawn great attention as alternative means of energy storage because of their low cost and resource availability. However, designing electrode materials with outstanding performances and excellent cycling efficiency remains a significant obstacle because of the substantial mass and large radius of Na-ions. Because of their high theoretical specific capacity and low cost, manganese (Mn)-based materials have greater potential to be explored compared with other transition-metal oxide anodes. From their current state of the art, the utilisations of Mn-based anode materials, including

Mn 3 O 4 is considered to be a promising anode material for sodium-ion batteries (SIBs) because of its low cost, high capacity, and enhanced safety. However, the inferior cyclic stability of the Mn 3 O 4 anode is a major challenge for the development of SIBs. In this study, a one-step solvothermal method was established to produce nanostructured Mn 3 O 4 with an average particle size of 21 nm and a crystal size of 11 nm. The Mn 3 O 4 obtained exhibits a unique architecture, consisting of small clusters composed of numerous tiny nanoparticles. The Mn 3 O 4 material could deliver high capacity (522 mAh g −1 at 100 mA g −1 ), reasonable cyclic stability (158 mAh g −1 after 200 cycles), and good rate capability (73 mAh g −1 at 1000 mA g −1 ) even without further carbon coating, which is a common exercise for most anode materials so far. The sodium insertion/extraction was also confirmed by a reversible conversion reaction by adopting an ex situ X-ray diffraction technique. This simple, cost-effective, and environmentally friendly synthesis technique with good electrochemical performance shows that the Mn 3 O 4 nanoparticle anode has the potential for SIB development.

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Owing to their high theoretical capacity, transition-metal oxides have received a considerable amount of attention as potential anode materials in sodium-ion (Na-ion) batteries. Among them, Mn3O4 has gained interest due to the low cost of raw materials and the environmental compatibility. However, during the insertion/de-insertion process, Mn3O4 suffers from particle aggregation, poor conductivity, and low-rate capability, which, in turn, limits its practical application. To overcome these obstacles, we have successfully prepared Mn3O4 nanoparticles distributed on the nitrogen (N)-doped and nitrogen, sulphur (N,S)-doped reduced graphene oxide (rGO) aerogels, respectively. The highly crystalline Mn3O4 nanoparticles, with an average size of 15–20 nm, are homogeneously dispersed on both sides of the N-rGO and N,S-rGO aerogels. The results indicate that the N-rGO and N,S-rGO aerogels could provide an efficient ion transport channel for electrolyte ion stability in the Mn3O4 electrode. The Mn3O4/N- and Mn3O4/N,S-doped rGO aerogels exhibit outstanding electrochemical performances, with a reversible specific capacity of 374 and 281 mAh g−1, respectively, after 100 cycles, with Coulombic efficiency of almost 99%. The interconnected structure of heteroatom-doped rGO with Mn3O4 nanoparticles is believed to facilitate fast ion diffusion and electron transfer by lowering the energy barrier, which favours the complete utilisation of the active material and improvement of the structure’s stability.