expansion during charge (300% when fully lithiated). [9][10][11][12][13] The build-up of mechanical stress through expansion of the active layer causes a loss of electrical contact with the non-expanding current collector, exacerbating capacity fade. Nanostructuring can alleviate mechanical stress build-up through smaller particle sizes, structural porosity and void spaces. [9,10] Nanoparticles (NPs), [14][15][16][17] nanowires (NWs), [18][19][20][21][22][23][24][25] and nanotubes (NTs) [26][27][28][29] are the most widely used morphologies, allowing for structural relaxation through shortened diffusion channels, increased porosity and larger surface area to volume ratios.Cu is the optimal current collector for lithium-ion battery anodes, due to its superior electrical conductivity over stainless steel (SS) and other carbon-based substrates. However, direct growth of Si on Cu yields electrochemically inactive CuSi compounds. [30][31][32] Alternatively, slurry-based Si electrodes suffer from issues of capacity fade as harsh expansion leads to electrical contact loss with the current collector. [33][34][35] Also, issues of capacity fade are heightened for thicker slurry layers, behaving similarly to bulk Si. [36,37] Si composites with graphite have gained huge popularity over recent years, synergistically combining the high lithiation capacity of Si with the low cost, stability, and scalability of carbon. [38][39][40][41][42] Graphite incorporation can alleviate instability issues common with Si-rich electrodes. [43,44] Karuppiah et al. demonstrated impressive long-term stability of slurry-based electrodes of Si NWs directly grown on graphite, retaining 87% capacity after 250 cycles versus Li metal. [44] Similarly, Datta et al. found that Si/graphite stability could be further enhanced through amorphous carbon coating, removing direct contact between Si and the electrolyte, and delivering a stable capacity of 660 mAh g −1 . [45] Slurry-based composites allow for high achievable Si loadings while maintaining anode stability. However, thick slurry layers suffer from poor fast-rate performance and inactive slurry additions negatively impact energy density. [46][47][48][49] The incorporation of Si into metallic or carbonbased frameworks like Mxenes, [50,51] graphene, [52,53] CNTs, [54,55] and CNFs [56,57] has allowed considerable improvements in cell stability, although the continued presence of inactive slurry components increases dead weight. Directly grown electrodes offer a multitude of advantages over slurry-based configurations, however, achieving stable performance of high loading binder-free Si electrodes has historically been difficult.High loading (>1.6 mg cm −2 ) of Si nanowires (NWs) is achieved by seeding the growth from a dense array of Cu 15 Si 4 NWs using tin seeds. A one-pot synthetic approach involves the direct growth of CuSi NWs on Cu foil that acts as a textured surface for Sn adhesion and Si NW nucleation. The high achievable Si NW loading is enabled by the high surface area of CuSi NWs and bolst...