Facile Synthesis of N‐Doped Carbon‐Encapsulated SnSe via Se‐Induced Conversion of SnS ₂ for High‐Performance Lithium‐Ion Batteries

SnSe is a promising lithium‐ion battery anode owing to its layered structure and high theoretical capacity, yet suffers from severe volume expansion and structural degradation. Herein, polyacrylonitrile‐derived nitrogen‐doped carbon‐coated SnSe/C composites were synthesized via ball milling and calcination, with the Se/SnS ₂ molar ratio tuned to optimize the structure. Characterization confirms uniform SnSe dispersion within the carbon matrix and a stable core–shell architecture. Electrochemically, the composite achieves an initial Coulombic efficiency of 80.8% at 0.1 A g ⁻¹ , delivers discharge capacities from 974.9 to 451.8 mAh g ⁻¹ over 0.1–5 A g ⁻¹ (excellent rate capability), and retains 777.9 mAh g ⁻¹ after 500 cycles at 1 A g ⁻¹ (94.0% retention), demonstrating outstanding long‐term cycling stability. Kinetic analysis reveals that the N‐doped carbon layer substantially enhances Li ⁺ diffusion and pseudocapacitive contribution. This work offers a facile and scalable route to high‐performance Sn‐based anodes.