Facile Synthesis of Nickel Nanofoam Architectures for Applications in Li‐Ion Batteries

Metal foams are utilized in various applications, such as in the automotive industries and for electrochemical devices. Herein, a Ni nanofoam is synthesized using a facile method for Li-ion batteries. Self-aligned Ni wires or randomly linked webs are produced with or without magnetic field, respectively. Ni granular beads or spiky clusters form at 370 or 450 degrees C, respectively. The surface area of Ni wires is increased by oxalic acid etching at 80 degrees C using 5-30wt% water, leading to Ni oxalate nanosheets, nanowires (NWs), or nanoleaves. Metallic Ni NWs are obtained by reducing Ni oxalate NWs with H-2 at 350 degrees C in 10 min. Carbon-coated Si nanoparticles on Ni NW foam (C-SiNP/NiNWF) show 38% rate enhancement (1222 vs. 889mAhg(-1)) in comparison to C-SiNP/Cufoil. Higher stability of C-SiNP/NiNWF with a capacity retention of 91% is reached vs. 73% for C-SiNP/Cufoil over 180cycles. The ambient-pressure solution process with low temperature and fast reaction time could make large-scale production plausible for these nanoarchitectures.