In-situ synthesis of freestanding porous SnOx-decorated Ni3Sn2 composites with enhanced Li storage properties

Abstract

In this paper, novel freestanding 3D hierarchical porous SnOx-decorated Ni3Sn2 (3D-HP SnOx@Ni3Sn2) composites are synthesized facilely by two-step chemical dealloying of designed as-cast Sn-45 at.% Ni alloy in different corrosive solutions. The results show that the 3D-HP SnOx@Ni3Sn2 composites have a typical bimodal pore size distribution composed of a micron-sized ligament-channel structure with highly nanoporous channel walls built by ultrafine SnOx (x = 1, 2) nanoparticles (3–6 nm). The unique 3D-HP composites as a binder-free integrated anode for lithium ion batteries (LIBs) display a significantly improved Li storage performance with first reversible capacity of 2.68 mAh cm−2 and good cycling stability with 85.1% capacity retention and over 98.4% coulombic efficiency after 100 cycles (just 0.004 mAh cm2 per cycle for capacity fading). This can be mainly ascribed to the synergistic effect between chemically inert 3D microporous Ni3Sn2 substrate with robust mechanical stress buffer and good transfer mass channels and in-situ growth of nanoporous SnOx with large specific surface areas and high electrochemical active sites. We believe that the present work can offer a promising anode candidate toward advanced LIBs.