Dual-ion batteries (DIBs) have recently attracted increasing attention owing to the merits of high voltage, high energy density, low cost, and environmental friendliness, which typically consist of graphite cathode for anion intercalation and graphite anode for Li+ intercalation. However, most of the reported DIBs are mainly based on Li-ion electrolyte, which hinders their long-term development taking into account of the limited and unevenly distributed lithium resource. Sodium-ion based DIBs thus show more promising potential owing to the merits of low cost. However, traditional graphite anode is not appropriate for Na-DIBs, owing to the larger size of Na+ that fails to reversibly intercalate/deintercalate into/from graphite anode. Therefore, designing appropriate anode materials plays an important role on developing high-performance Na-DIBs.

A research group led by Prof. TANG Yongbing from Shenzhen Institute of Advanced Technology (SIAT), Chinese Academy of Sciences has firstly constructed a novel MoS2/C-graphite DIB (named as MoS2/C-G DIB) based on a sodium-ion electrolyte, employing penne-like MoS2/C nanotube as anode material and expanded graphite as cathode material. The hierarchical MoS2/C nanotube can supply a significantly expanded (002) interlayer spacing with 0.98 nm of the 2H-MoS2, which facilitates fast Na+ insertion/extraction reaction kinetics, thus contributing to improved DIB performance. As a result, the MoS2/C-G DIB was demonstrated to deliver a reversible discharge capacity of 65 mAh g-1 at 2 C over the voltage range of 1.0-4.0 V, which also exhibited good cycling stability for over 200 cycles with 85% capacity retention. All these results indicate that the design of MoS2/C-G DIB paves a new avenue for developing high-performance and low-cost energy storage devices.

The paper entitled “Penne-like MoS2/carbon nanocomposite as anode for sodium-ion-based dual-ion battery” has been published in Small.

The research work has been supported by the National Nature Science Foundation of China, Shenzhen Peacock Plan, and Shenzhen Science and Technology Planning Project.