Novel three dimensional hierarchical porous Sn-Ni alloys as anode for lithium ion batteries with long cycle life by pulse electrodeposition

In this paper, novel three dimensional hierarchical porous Sn-Ni (3D-HP Sn-Ni) alloys were investigated as a promising anode for high-performance Li ion batteries (LIBs), which was fabricated by pulse electrodeposition of mesoporous Sn-Ni alloy made of ultrafine nanoparticles on the 3D nanoporous copper substrate from chemical dealloying of as-cast Al55Cu45 (at.%) alloy slices in the HCl solution. The results show that the as-obtained 3D-HP Sn-Ni alloys are typically characteristic of open, bicontinuous, interpenetrating bimodal pore size distribution comprising large-sized (hundreds of nm) ligament-channel network architecture with highly porous channel walls (several nm). Compared to the two dimensional nanoporous Sn-Ni (2D-NP Sn-Ni) thin films, the 3D-HP Sn-Ni alloys as anode for LIBs show superior cycling stability with reversible specific capacity of 0.25 mAh cm−2 and coulombic efficiency of more than 95% up to 200 cycles. Moreover, the reversible capacity as high as 0.22 mAh cm−2 can be achieved even after a series of high-rate charge–discharge cyclings. The satisfactory electrochemical properties can be mainly ascribed to the unique 3D hierarchical porous structure, large contact surface area between active material and electrolyte, as well as good buffer effect of inactive component, which is greatly beneficial to alleviate the huge volume variation, enhance the loading mass of active material, shorten the Li+ migration distance and improve the electron conductivity. We believe that this present work can provide a promising anode candidate towards practical application of high-performance LIBs.