Rational Design of Carbon-Encapsulated Ce-Regulated SnSe/MnSe Heterostructured Nanocomposites for High-Performance...

Metal selenides are attractive options for the anode in lithium-ion batteries because of their adjustable topologies and high theoretical capacity. Nonetheless, their lack of structural stability hinders their marketing. Elemental doping and heterostructure engineering have proven ways to deal with these problems. In this study, Ce-doped MnSn(OH)₆ was fabricated by the co-precipitation method and coated with polydopamine as a precursor. The precursor has been subjected to in situ carbonization and selenization annealing. A novel metal selenide composite, which integrates a cubic bimetallic SnSe/MnSe heterostructure encapsulated in nitrogen-doped carbon with Ce-modulated heterointerfaces, has been yielded, denoted as Ce-SnSe/MnSe@NC. The unique heterointerface design and Ce doping modulation enhance the electrochemical performance during the charge/discharge cycles. The Ce-SnSe/MnSe@NC electrode exhibits remarkable electrochemical performance, retaining a high reversible capacity of 849 mAh g^-1 after 200 cycles at 100 mA g^-1 (86% retention); even at 10 A g^-1, a capacity of 264.7 mAh g^-1 is attainable. Through Li⁺ kinetics characterization, it was found that the Ce-SnSe/MnSe@NC electrode exhibited superior lithium adsorption properties and ion transport properties. The assembled soft-pack battery with the Ce-SnSe/MnSe@NC electrode achieved a gravimetric energy density of 363 Wh kg^-1. This rare-earth element-regulated heterointerface engineering strategy opens up new avenues for developing advanced alkali-metal batteries.