Stable high areal capacity lithium-ion battery anodes based on three-dimensional Ni–Sn nanowire networks

Nanowire arrays present an excellent candidate for high performance lithium-ion battery electrodes. However, agglomeration in long nanowire arrays impedes nanowire-based electrodes from delivering high areal capacity, by degrading the nanoscale wires to micro-sized bundles and reducing the mechanical stability. In this study, we develop a simple way to fabricate three-dimensional (3D) nickel–tin (Ni–Sn) nanowire networks by using 3D porous anodic alumina templates synthesized from low-cost impure aluminum foils. By eliminating agglomeration, stable high areal capacity anodes are demonstrated with 3D self-supporting Ni–Sn nanowire network structures. With a nanowire length of 40 μm, the 3D Ni–Sn nanowire networks can deliver an areal capacity as high as 4.3 mAh cm−2 with a cycle life longer than 50 cycles. The 3D Ni–Sn nanowire networks also exhibit an excellent rate capability with 72% of the capacity retained when the test rate increases from C/5 to 6C.

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► Agglomeration in long straight nanowire arrays causes performance.
► 3D nanowire networks are fabricated using 3D PAA templates.
► Electrochemical performance of 3D nanowire networks is length-independent.
► Linear increase of areal capacity with active material mass loading is realized.