Controlling Lithium Surface Diffusivity via 2D PtTe₂, PdTe₂, and NiTe₂ Coatings for Anode‐Free and Lithium Metal Batteries

Abstract

AbstractAnode‐free Li‐ion batteries (AFLBs) and Li‐metal batteries (LMBs) offer superior energy densities compared to conventional Li‐ion batteries with graphite anodes. However, they degrade faster owing to their lower Coulombic efficiency, primarily caused by uneven Li deposition on the current collector (CC) in AFLBs or the Li‐metal anode (LMA) in LMBs. Coating CCs and LMAs has emerged as a promising strategy to enhance the CE. Coating CCs and LMAs with PtTe2, PdTe2, and NiTe2—metallic 2D transition metal dichalcogenides—reveals the critical factors for achieving uniform Li plating. The PtTe2 coating facilitates rapid Li surface diffusivity, while the PdTe2 and NiTe2 coatings provide shorter diffusion paths for Li adatoms on the CCs and LMAs. In addition, Li2Te, formed as a byproduct of the decomposition of PdTe2 and NiTe2 during Li plating, reduces the critical nucleus size by minimizing the interfacial energy between the electrolyte and the plated Li. PtTe2 more effectively enhances the AFLB cycling performance, whereas PdTe2 and NiTe2 are more advantageous for LMBs. Notably, a 5‐nm‐thick PdTe2 coating on the LMA achieves 80% capacity retention after 450 cycles using a LiFePO4 cathode (3 mAh cm−2) at a 0.5 C‐rate.