A Scalable Dendritic Si‐Clad NiSn Anode via One‐Step Electrodeposition with Ultrahigh Areal Capacity for Micro Lithium‐Ion Battery

High energy density, long cyclability, and enhanced stability in a small footprint achieved through microfabrication are crucial for micro lithium‐ion batteries. Herein, a 3D Si‐clad NiSn anode characterized by a dendritic NiSn network and silicon nanoparticles is proposed. The dendritic network facilitates fast ion/electron transfer and provides expansion space for the silicon, while the uniformly distributed silicon enhances capacity and stability. The anode, scalable to the hundred‐micron scale, is fabricated via one‐step electrodeposition incorporating the dynamic template technique. This technique generates interconnected pores extending from the inner to the outer surface of the anode, facilitating electrolyte penetration and ion transport. As a result, the anodes in the Swagelok cells exhibit an ultrahigh areal capacity of up to 28.2 mAh cm −2 and an enhanced stability of 91% capacity retention after 300 cycles. The dendritic Si‐clad NiSn anode, based on microfabrication, presents an excellent opportunity to advance micro energy systems.