Defect-rich Ni₃Sn₄ quantum dots anchored on graphene sheets exhibiting unexpected reversible conversion reactions with exceptional lithium and sodium storage performance

In the present study, a simple, ultrafast microwave irradiation procedure is employed to develop low-cost, zero-band-gap Ni₃Sn₄ quantum dots (~4–6 nm in size) with abundant nanopores. These quantum dots are uniformly anchored on reduced graphene oxide (rGO) sheets, which are then utilized as anode materials for both Li⁺ and Na⁺ storage. This rational defect engineering approach can cause unexpected, fully reversible conversion reactions and pseudocapacitive interfacial Li/Na storage mechanisms. The nanopores also offer unblocked pathways for Li⁺/Na⁺ ion transfer and significantly improve the electrical conductivity. Furthermore, the synergistic effects of ultrasmall Ni nanoparticles and rGO sheets solve the crucial challenges of coarsening Sn nanocrystals and severe volume changes that occur during repeated cycles, thereby delivering remarkable initial discharge capacities, excellent rate capability, and exceptional cyclic performance for ultradurable cycling in both the Li-ion and Na-ion batteries. More importantly, this simple, fast approach opens an effective avenue for the design and fabrication of various porous, defect-enriched nanomaterials for different applications.