Binary-Metal Mn₂SnO₄ Nanoparticles and Sn Confined in a Cubic Frame with N-Doped Carbon for Enhanced Lithium and...

Sn-based materials have been popularly researched as anodes for energy storage due to their high theoretical capacity. However, the sluggish reaction kinetics and unsatisfied cycling stability caused by poor conductivity and dramatic volume expansion are still pivotal barriers for the development of Sn-based materials as anodes. In this work, the binary-metal Mn₂SnO₄ nanoparticles and Sn encapsulated in N-doped carbon (Sn@Mn₂SnO₄-NC) were fabricated by multistep reactions and employed as the anode for lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs). The coexistence of binary metals (Sn and Mn) can improve intrinsic conductivity. Simultaneously, hollow architecture along with carbon relieves internal stress and prevents structural collapse. A Sn@Mn₂SnO₄-NC anode delivers an appealing capacity of 1039.5 mAh g^-1 for 100 cycles at 100 mA g^-1 and 823.8 mAh g^-1 for 600 cycles at 1000 mA g^-1 in LIBs. When evaluated as an anode in SIBs, the Sn@Mn₂SnO₄-NC anode tolerates up to 7000 cycles at 2000 mA g^-1 and maintains a capacity of 185.8 mAh g^-1. Quantified kinetic investigations demonstrate the high contribution of pseudocapacitive effects during the cycle process. Furthermore, density functional theory (DFT) calculations further verify that introduction of the second metal (Mn) improves the conductivity of the material, which is favorable for charge transport. This work is expected to provide a feasible preparation strategy for binary-metal materials to enhance the performance of lithium- and sodium-ion batteries.