Cationic Organic Polymers With Electrostatic Shielding Effect and Lithiophilic Sites for Dendrite-Free Lithium Metal Batteries.

Uncontrolled lithium dendrite growth and persistent electrolyte breakdown present major safety challenges, limiting the practical deployment of lithium metal batteries (LMBs). In this study, a unique organic polymer (Ni-HAT CN), rich in lithiophilic sites and cationic groups, is designed as a protective layer for lithium metal anodes (LMAs) to enable uniform lithium deposition and enhance Li+ flux. On one hand, the positively charged Ni2+ sites in the polymer modify the electronic structure and provide robust electrostatic shielding to suppress adverse side reactions. On the other hand, the dense lithiophilic sites (C═N, C≡N, etc.) in HAT CN facilitate Li+ diffusion and accelerate the desolvation process of Li+. Furthermore, the in-depth working mechanisms behind these effects are revealed through a variety of in situ/ex situ characterizations and theoretical calculations. As a result, the Li+ transference number of the Ni-HAT CN-protected battery increases to 0.76, and it exhibits stable cycling for over 3000 h (3 mA cm-2). The full cell maintains high capacity after 900 stable cycles at 1 C, with an average ultra-low degradation rate of just 0.047% per cycle. This work offers a novel strategy for stabilizing LMAs by uniquely combining electrostatic field construction with the regulation of solvation structures.