The wires produced in this way are 3 to 20 times thicker than most of the reported nanowires, which have diameters in the 50- to 300-nm range.   With the first technique, nanowires usually in a random arrangement are obtained. This

production process is limited with respect to the wire density, diameter control, wire length, and array stability. Moreover, an efficient low-resistivity connection to a current SYN-117 clinical trial collector is not easy with this technique. Method 2 overcomes some problems of technique 1, and may be easier than method 3 from a process point of view, but has a click here number of limits with respect to optimizing the array geometry and attaching to a current collector. For the moment, there are no reports of pores ABT-888 datasheet or wires with modulated diameter by method 2, and thus, for

the moment, it is not possible to fabricate interconnected wires forming a free-standing array of long wires. Having a free-standing array is important for the deposition of a mechanically stable metal contact at one side. A new concept of Si anodes has been developed by technique 3, which consists of an array of Si microwires embedded at one end in a Cu current collector [9]. The capacity of the anodes is very stable over 100 cycles [2] and breaks all the records when considering the capacity per area (areal capacity) [10]. In the present work, the scalability of the production process will be discussed. As will become clear in the following lines, the capacity of the anodes is also scalable, with certain limits in the cycling rate. Methods The production process of the Si microwire anodes, depicted in Figure  1, consists of four main steps: (a) electro-chemical etching of macropores with modulated diameters. Sections with narrower diameters are created in order to produce (two) stabilization planes in the final wires. The starting material is Si wafers with a structure of pits defined by contact lithography. (b) The second step is chemical over-etching in KOH-based solutions of the pore walls;

this step is done until the pores merge and wires remain. Commonly, the wires are produced with a diameter of around 1 μm. (c) The third step is electroless deposition of a Cu seed layer until certain depth. (d) The fourth Phospholipase D1 step is electrochemical deposition of Cu on the Cu seed layer to create a current collector of the final anode. After this step, the anode is separated from the Si substrate by pulling from the Cu layer. Additional information of the fabrication process can be found in [9]. Figure 1 Process steps for the production of Si microwire anodes. (a) Electrochemical etching of macropores with modulated diameters. (b) Chemical over-etching of the pores to produce wires. (c) Electroless deposition of a Cu seed layer. (d) Electrochemical deposition of the Cu current collector.