MXene-anchored TTPP-stabilized Co single atoms for accelerated kinetics and durable Li–Cl2 batteries

Abstract

Li–Cl₂ batteries are promising candidates for future energy storage due to their high theoretical energy density and wide operating temperature range. However, their practical application is severely hindered by the weak affinity for Cl₂ and sluggish LiCl/Cl₂ conversion kinetics. Herein, we report a synergistic cathode design that integrates Co single atoms anchored on 5,10,15,20-tetra(4-(1,2,4-triazol-1-yl)phenyl)porphyrin (SACo-TTPP) with conductive Mo₂TiC₂T_x MXene, forming an SACo-TTPP@Mo₂TiC₂T_x composite. Structural evidence indicates the formation of well-distributed, Co–N₄ configurations within the MXene. The SACo-TTPP@Mo₂TiC₂T_x cathode shows superior electrochemical performance due to SACo-TTPP's Cl₂ adsorption, Co catalysis, and MXene's high conductivity. The Li–Cl₂ battery demonstrates a high reversible capacity of 971.7 mAh g⁻¹ with a coulombic efficiency of 97.2% after 100 cycles at 400 mA g⁻¹. Moreover, the SACo-TTPP@Mo₂TiC₂T_x cathode displays superior rate performance and sustained cycling stability for 850 cycles at 2000 mA g⁻¹, along with impressive performance at a low temperature of −20 °C. Furthermore, the Li–Cl₂ pouch cells demonstrate stable operation and practical feasibility. Density functional theory (DFT) calculations reveal that SACo-TTPP effectively enhances Cl₂ adsorption and reduces the energy barrier for LiCl/Cl₂ conversion, thereby accelerating reaction kinetics and improving reversibility. This work provides a new strategy for designing high-performance cathodes for Li–Cl₂ batteries and highlights the synergistic effect between single-atom catalysts and MXene supports.