Constructing Al@C–Sn pellet anode without passivation layer for lithium-ion battery

Al is considered as a promising lithium-ion battery (LIBs) anode materials owing to its high theoretical capacity and appropriate lithation/de-lithation potential.Unfortunately,its inevitable volume expansion causes the electrode structure instability,leading to poor cyclic stability.What’s worse,the natural Al2O3layer on commercial Al pellets is always existed as a robust insulating barrier for electrons,which brings the voltage dip and results in low reversible capacity.Herein,this work synthesized core–shell Al@C–Sn pellets for LIBs by a plus-minus strategy.In this proposal,the natural Al2O3passivation layer is eliminated when annealing the pre-introduced SnCl2,meanwhile,polydopamine-derived carbon is introduced as dual functional shell to liberate the fresh Al core from re-oxidization and alleviate the volume swellings.Benefiting from the addition of C–Sn shell and the elimination of the Al2O3passivation layer,the as-prepared Al@C–Sn pellet electrode exhibits little voltage dip and delivers a reversible capacity of 1018.7 mAh·g–1at 0.1 A·g–1and 295.0 mAh·g–1at 2.0 A·g–1(after 1000 cycles),respectively.Moreover,its diffusion-controlled capacity is muchly improved compared to those of its counterparts,confirming the well-designed nanostructure contributes to the rapid Li-ion diffusion and further enhances the lithium storage activity.