A High‐Energy Aluminum‐Fluorinated Carbon Battery Enabled by Chemical Bond Activation in Molten Salt Electrolytes

Abstract

ABSTRACT Aluminum‐fluorinated carbon (Al─CF x ) primary batteries show potential in aerospace, military, and related fields, due to the inherent safety and abundance of aluminum, long‐term reliability, and high theoretical energy density. However, the practical performance of these batteries is impeded by high energy barriers for Al 3+ desolvation and C─F bond cleavage, which leads to slow kinetics and thereby restricts the achievable energy density. Here, we report a high‐energy Al─CF x primary battery via a chemical bond activation strategy in molten salt electrolytes. The designed quaternary molten salt contains electrochemically active high‐order Al─Cl clusters to accelerate Al 3+ desolvation; crucially, abundant alkali metal ions activate CF x ’s C─F bonds via strong electrostatic attraction, promoting stable AlF 3 formation. Operated at 85°C and 10 mA g −1 , this battery achieves a discharge plateau of 1.75 V and a specific capacity of 897.7 mAh g −1 , outperforming the ionic liquid system (0.21 V, 464.4 mAh g −1 ). A high‐rate Al─MnO 2 @CF x battery is developed via engineering a MnO 2 ─CF x heterointerface, offering a low‐cost route for high‐energy‐density energy storage.