Regulation of lithium ion transport dynamics via carbonized-polymer-dots modified substrate to achieve 2 mV ultralow voltage hysteresis

Abstract

The practical implementation of lithium metal remains challenging because of unregulated Li dendrite growth, which results in safety hazards and poor cycling performance. Herein, a stable three-dimensional (3D) hybrid architecture with low voltage hysteresis is fabricated through modifying N, O-codoped carbonized-polymer-dots (CPDs) on carbon-based substrate (CPDs-GCC). CPDs provide abundance of lithiophilic nitrogen-containing functional groups and carbonyl, which can direct the homogenous deposition of lithium and reduce the growth of Li dendrites. Moreover, the CPDs-based lithiophilic anode reduces the migration energy barrier and activation energy of Li⁺, enhances the exchange current density, and effectively enhances the ion transport kinetics and ion reaction kinetics at the electrode–electrolyte interface. As a result, the half cells with a capacity of 3 mAh cm^-2 allow an ultralow voltage hysteresis of ~ 2 mV over 4800 h at 2 mA cm^-2. The full cell with LiFePO₄ cathode demonstrates outstanding cycle stability with a capacity retention of 95% after cycling 3000 cycles at 0.2 A g^-1. This study examines the factors influencing voltage hysteresis, explores its impact on battery performance, and proposes a simple method to mitigate it. This lays the foundation for the development of high-performance batteries.