A pinning structure via composing laminar rGO with fragmented MoS2 toward fast and stable sodium and lithium-ion storage

The diffusion of lithium ions and sodium ions in the anode materials is the main factor limiting the fast-charging performance of lithium and sodium-ion batteries. Due to the slow diffusion kinetics, taking lithium-ion batteries as an example, lithium ions and electrons accumulate locally in and on the surface of anode materials, especially in the process of fast-charging, resulting in uneven lithiation reaction and enormous transient stress, which leads to poor fast-charging performance. In this work, from the aspect of solving the ion diffusion rate, a capacitive type of energy storage is introduced by designing MoS2/rGO composite materials with pinned structures as fastcharging and stable anode materials for lithium-ion batteries and sodium-ion batteries. Combining the high ion conductivity and structural rigidity of the rGO conductive network with a few-layer MoS2 provides a high ion diffusion rate and capacity. As expected, it can charge to 69 % in 25 min and 44 % in 3.2 min, respectively, providing a high capacity of 214.2 mAh g-1 at 10 A g-1 and a high-capacity retention of 85.31 % after 1, 000 cycles at the current density of 3 A g-1 in sodium-ion batteries. Similarly, the high reversible capacity of 910.5 mAh g-1 is achieved in the lithium-ion batteries, and there is almost no capacity loss after 1, 000 cycles at a high current density of 2 A g- 1. This work may provide a reference for designing more fast-charging anode materials with high capacity.

Automated summary

The diffusion rate of ions in the anode materials is crucial for the fast-charging performance of lithium and sodium-ion batteries. By designing MoS2/rGO composite materials with pinned structures, the ion diffusion rate and capacity can be improved, resulting in high capacity and stability for fast-charging.