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

ABSTRACT 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 Ni 2+ 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.