1. EXAFS cannot distinguish C from O due to similar atomic numbers (Z=6 vs. 8) and nearly identical bond lengths. Your DFT claim that Cu–O binding energy is greater than zero lacks numerical data and is not a standard stability criterion (binding energy should be negative for stable adsorption). Given that Cu typically favors N/O coordination, what direct spectroscopic evidence (e.g., XANES pre-edge, or ¹³C NMR) confirms the exclusive Cu–C₃ configuration over a Cu–O–C moiety, and why did you not consider Cu–C₄ or Cu–C₂ structures?
2. The b-values (0.50–0.60) indicate a strictly diffusion-controlled process, yet your electrode delivers near-theoretical capacity (403 mAh g⁻¹) at 30 A g⁻¹ (a 150-fold rate increase) with almost no decay. How can a diffusion-limited system sustain such ultrahigh rates? Please provide the actual Na⁺ diffusion coefficients (D) from GITT and compare them with literature values for Bi-based anodes—this seems orders of magnitude too high for a solid-state alloying reaction.
3. You claim the Cu–C₃ sites catalyze more decomposition of NaPF₆ and DME, yielding higher NaF (35.5% vs. 12.7%) and Na₂CO₃, yet the SEI is thinner (6 nm vs. 12 nm). More inorganic products should increase mass and thickness; this is a direct contradiction. Did you quantify the total SEI volume or mass (e.g., via XPS total intensity or EQCM) to confirm that the absolute amount of decomposition is actually lower, and if so, how does catalysis lead to less overall decomposition?
4. (a) Figure 2b,e,i,j list CuO as a reference three times, but the text mentions Cu₂O—this is a clear error. (b) You assign a lattice fringe of 0.241 nm to NaF (200); however, the standard PDF card for NaF gives d(200) = 0.231 nm. This mismatch (~4%) is beyond typical TEM error. Please clarify the actual phase and verify your indexing.
5. You report 265 Wh kg⁻¹ based on total active mass of anode and cathode. However, the anode: cathode mass ratio is 1:3, meaning the cathode mass dominates. What is the practical energy density when including electrolyte, separator, and current collectors? Without this, the value is misleading for practical application.
