In-depth Li⁺ transportation in three-dimensionalized nanodiamond network for improved liquid and solid lithium metal batteries

Confining lithium (Li) deposition in three-dimensional scaffold is commonly employed to suppress Li dendrite and enhance the cycling stability of next generation Li metal batteries (LMBs). However, the efficiency of this strategy is often degraded under lean-Li conditions, due to the serious precipitation of deposited Li on the top surface of the electronic conducting scaffold such as carbon or metal matrix. Here it is found that building an insulating interlayer on the scaffold but with a high Li⁺ transfer dynamism, can be a promising strategy to address the above challenge. We successfully three-dimensionalize an insulating and robust nanodiamond (ND) network on carbon paper (CP) via chemical vapor deposition, which not only retards the electron transfer to avoid the top Li precipitation, but also exhibits impressive Li affinity and mobility to undergo an in-depth Li⁺ transportation throughout the scaffold. Based on this advanced three-dimensionalized ND network, the Li anode performance in CP@ND significantly exceeds that in the traditional carbon fiber matrix, particularly under lean-Li conditions. Furthermore, the application of CP@ND leads to a sharply improved cyclability of all-solid-state LMBs, establishing a novel guideline of protecting Li anode in the electrolyte-mobility-limited environment.