{"id":"ac46568d-94a9-4f7d-9806-a16ba4dd3999","arxiv_id":"2411.10920","paper_version":2,"verdict":"CONDITIONAL","confidence":"MODERATE","novelty_score":6.0,"correctness_risk":"medium","formal_verification":"none","parameter_count":7,"one_line_summary":"METS uses frequency-dependent thermal waves from electrochemical heating to measure solvation entropy, charge-transfer resistance, and interfacial transport resistance at individual electrodes in operating lithium-ion cells.","lead":"This paper introduces a thermal-wave technique called METS that measures heat generated at different harmonics of an AC current to map battery interfacial properties, such as solvation entropy and ion-transport resistance, at specific electrode-electrolyte interfaces during operation. It could give battery developers a way to watch interfaces like the SEI layer grow in real time without opening the cell.","discovery_kind":"new_method","skeptic_critique":{"model":"deepseek-v4-flash","headline":"The 2ω charge-transfer/transport decomposition is unidentifiable: Fig. 6 states the signal is insensitive to R_CT, so the reported R_CT values are imposed, not measured.","rationale":"I read the paper in good faith as proposing a genuinely new operando thermal-wave diagnostic. The 1ω entropy results are internally consistent and agree with literature values, and the two-sensor NMC-graphite experiment provides a strong check of the depth-resolved entropic-coefficient assignment. The 2ω total interfacial resistance broadly reproduces EIS totals in most cells, and the depth separation between the two interfaces appears supported by the sensitivity structure and by the foil-versus-electrodeposited contrast. The load-bearing weakness is exactly the one the reader identified: the claimed measurement of charge-transfer resistance is not supported because the METS 2ω signal is explicitly insensitive to R_CT in the regime studied. This is not an external disagreement about electrochemical interpretation; it is an internal identifiability problem stated in the paper's own Figure 6 caption and SI. In the small-overpotential limit, Butler-Volmer kinetics linearize, so the current-amplitude dependence that is supposed to distinguish kinetic from ohmic heating disappears. The reported R_CT values with uncertainties comparable to or larger than the values, and the multilayer analysis that simply assumes a small R_CT, corroborate that these quantities are imposed rather than fitted. The consequence is that the central claim of resolving interfacial impedance into charge-transfer and transport components is only half supported: transport resistance separation between interfaces is plausible, but charge-transfer resistance is not measured. This does not invalidate METS as a whole, but it requires the paper to reframe the charge-transfer claim or demonstrate identifiability. The reader's CONDITIONAL verdict is therefore appropriate, and my stress-test does not change it.","tokens_in":32200,"tokens_out":3090,"duration_ms":35276,"concrete_test":"Refit the 2ω spectra of Figures 5 and 6 (and SI Figure S12) with R_CT fixed at values spanning 0.01, 0.5, 2, 5, and 10 Ω (equivalently, exchange current density varied over orders of magnitude), while allowing all transport resistances to float freely. If the best-fit χ² changes negligibly while the fitted transport resistances move by more than their reported uncertainties, the decomposition is unidentifiable and the reported R_CT values must be labeled as assumptions rather than measurements. If a clear χ² minimum emerges near the reported R_CT values, the objection is resolved.","verdict_should_be":"UNCHANGED","load_bearing_attack":"The central 2ω claim is that the nonlinearity of Butler-Volmer kinetics separates charge-transfer resistance from interfacial transport resistance by fitting spectra at multiple current amplitudes. That separation requires the 2ω signal to have measurable sensitivity to R_CT in the operating regime. The paper's own sensitivity analysis contradicts this: Figure 6(c,d) and its caption state that both in-phase and out-of-phase 2ω temperatures are not very sensitive to exchange current density (and hence R_CT) at either interface, and the main text says sensitivities to small charge-transfer resistance are small compared with transport resistance. With the reported values of R_CT near 0.2–0.5 Ω and currents of 12–22 mA, the overpotential is only ~10 mV, well inside the linear Butler-Volmer regime (RT/F ≈ 25.7 mV at room temperature). In that regime kinetic heat generation scales as I², exactly like ohmic transport heat, so changing current amplitude cannot separate the two processes. The reported uncertainties confirm the problem: symmetric-cell R_CT is 0.5 ± 0.88 Ω, where the uncertainty exceeds the value; the multilayer cell analysis explicitly 'assumes a small charge-transfer resistance (0.2 Ω)' (SI Section 12). Thus R_CT values are model priors, not measurement outcomes. If the true R_CT were non-negligible, the fitted transport resistances would shift correspondingly, so the claimed resolution into charge-transfer and transport components is not established. The 1ω entropy measurement and the total 2ω interfacial resistance matching EIS remain credible; the load-bearing problem is specifically the charge-transfer/transport decomposition.","agreement_with_reader":"agree"},"referee_report":{"model":"deepseek-v4-flash","summary":"The paper introduces Multi-harmonic Electro-Thermal Spectroscopy (METS), an operando technique in which an AC current drives an electrochemical cell while a lock-in resistance thermometer on the cell exterior records 1ω and 2ω temperature oscillations. Thermal penetration depth is used to attribute heat sources to specific electrode–electrolyte interfaces, and the harmonic content is used to separate reversible entropic heat (1ω) from irreversible ohmic and kinetic heat (2ω). The 1ω spectra are fitted to yield entropic coefficients at each interface (1.2 mV/K for a Li symmetric cell; 1.3 and 1.0 mV/K for an NMC–Li cell; 1.05 and 1.33 mV/K for an NMC–graphite cell), with literature agreement in all three configurations. The 2ω spectra at multiple current amplitudes are fitted to extract interfacial transport and charge-transfer resistances at each electrode and to track SEI growth. The paper claims depth resolution of a few microns and validation against EIS, and it reports the 2ω decomposition as the central new capability.","tokens_in":32498,"tokens_out":26062,"duration_ms":263770,"significance":"The 1ω entropy measurement is the strongest part of the paper: per-interface solvation entropy in an operating cell is a genuinely new observable, and the authors support it with quantitative agreement against literature values in three independent cell configurations, including a falsifiable dual-sensor sign-reversal test in an NMC–graphite cell. The SI also contains a clean control experiment (a serpentine heater with an independently measured resistance, fit to within 5%) that validates the thermal-analysis chain. If the 2ω claims are corrected, the technique still provides per-interface total interfacial resistance without symmetric-electrode assumptions, which is useful for identifying defective electrodes. However, the claimed separation of charge-transfer resistance from interfacial transport resistance is not supported by the paper's own sensitivity analysis and uncertainty quantification: the reported R_CT values are effectively priors. The 'few microns' depth-resolution claim in the abstract is likewise not supported by the demonstrated interface-level attribution.","major_comments":[{"comment":"The decomposition of the 2ω interfacial impedance into charge-transfer and transport components is not identifiable in the reported operating regime, and the paper's own diagnostics confirm the reviewer's concern. The Figure 6 caption states that 'both in-phase and out-of-phase temperature measurements are also not very sensitive to the exchange current density (conversely the charge-transfer resistance) at both interfaces,' and the main text states that sensitivities to charge-transfer resistance are small compared with those to transport resistance. This is expected from the operating point: with R_CT ≈ 0.2–0.5 Ω and I0 = 12–22 mA, the peak overpotential is 2.4–11 mV, well below RT/F ≈ 25.7 mV, so the Butler–Volmer relation is in its linear regime and kinetic heat I²R_CT is functionally identical to ohmic transport heat I²R_SEI; the sub-quadratic nonlinearity invoked for separation is a correction of order (Fη/2RT)² ≈ 1%, far below the ~10% measurement noise. Consistent with this, the reported R_CT values are identical at both electrodes in every cell (0.5/0.5 Ω in Tables 1 and 2; 0.2/0.2 Ω in the NMC row), carry uncertainties that include zero (0.5 ± 0.88 Ω in Table 1), and are explicitly imposed in SI §12 ('assuming a small charge-transfer resistance for both (0.2 Ω)'). The four-component resolution claimed in the abstract and Introduction is therefore a model prior, not a measurement outcome; if the true R_CT were non-negligible, the reported transport resistances would shift by the same amount. The 2ω analysis should be reframed to report per-interface total resistance (R_SEI + R_CT) with R_CT given as an upper bound, or the nonlinear-regime operation (η ~ RT/F) must be demonstrated with a control in which R_CT is independently varied.","section":"2ω analysis; Fig. 6(c)–(d); Table 1; SI §12"},{"comment":"The claim that EIS provides independent per-interface validation is not supported by Table 1. For the NMC–Li cell, EIS attributes 2.26 ± 0.23 Ω to the lithium interface and 10.1 ± 1.0 Ω to the cathode, whereas METS yields 0.5 + 0.2 = 0.7 Ω and 12.2 + 0.2 = 12.4 Ω for the same two interfaces. The anode discrepancy of ~1.56 Ω is about 5σ with respect to the combined uncertainties and is not discussed; only the totals agree (13.1 vs 12.36 Ω). The same direction of bias appears in the post-SEI electrodeposited cell, where METS assigns 3.26 + 0.5 = 3.76 Ω to the near electrode versus 4.6 ± 0.46 Ω from EIS, but 32.6 + 0.5 = 33.1 Ω to the far electrode versus 22.3 ± 2.23 Ω from EIS. This systematic pattern of over-attributing resistance to the far interface suggests a depth-attribution or heat-source-modeling issue (for example, in the uniform volumetric-heating assumption for the porous cathode or in the thermal interface resistance inputs) and must be explained or quantified before the per-interface claims can be regarded as validated.","section":"Table 1, NMC–Lithium row"},{"comment":"The abstract's claim of 'depth resolution of a few microns' is not supported by the demonstrated capability or by the paper's own statements. SI §5 states that the measurement cannot significantly differentiate the spatial distribution of heat within the 60-µm porous cathode, and that the assumed interfacial heat-generation location (15 nm versus 1 µm) does not affect the results. At the highest measured frequency (30 Hz), the thermal penetration depth in the electrode materials is of order 0.5 mm, larger than the ~100–200 µm stack, so the measurements discriminate heat sources at two interfaces separated by roughly 100 µm rather than localizing heat to micron scales. The abstract should be reworded to claim interface-level attribution within a known stack geometry, or a dedicated resolution test should be provided.","section":"Abstract; SI §5"},{"comment":"The consistency between the METS and EIS totals is marginal in the post-SEI electrodeposited cell and is not addressed. Table 2 reports a METS total of 35.8 ± 6.28 Ω versus an EIS total of 26.9 ± 2.7 Ω; the 8.9 Ω difference is about 33% of the EIS value and exceeds the combined 1σ uncertainty. In addition, the pre-SEI total (18.1 Ω) includes the two 0.5 Ω charge-transfer contributions, while the post-SEI total (35.8 Ω) excludes them (3.26 + 32.6 = 35.86), so the table is arithmetically inconsistent in how the reported 'Total' is formed. The growth in discrepancy after SEI growth should be quantified and explained, since the SEI-growth demonstration is a headline application.","section":"Table 2, post-SEI growth row"}],"minor_comments":[{"comment":"The sign-convention discussion around Figure 2 is internally contradictory: the text first states 'at higher frequencies (>1 Hz) ... the in-phase temperature rise is positive for a positive entropic heating at Interface 1' and then, a few sentences later, 'for Interface 1, at higher frequencies (>1Hz, short penetration depth), the in-phase temperature rise is negative while at lower frequencies ... the in-phase temperature rise is positive'; the intervening sentence invoking Feldman's solution also mixes the in-phase and out-of-phase terms ('the out-of-phase temperature rise is negative'). These statements should be corrected and made consistent with the figures and with SI §9.","section":"Figure 2 discussion, main text"},{"comment":"In the NMC–Li description, the sentence 'the out-of-phase temperature is not cancelled at lower frequencies (<1Hz), and theoretically keeps rising as the frequency increases' appears to mean 'as the frequency decreases'; the direction of the frequency sweep should be corrected.","section":"Figure 2(b) discussion, main text"},{"comment":"Several cross-references are inconsistent: the post-SEI paragraph cites 'Figure 5 (b)' for the EIS spectrum that is shown in Figure 4(b); the comparison table for the electrodeposited cell is called 'Table 3' in the text but is captioned 'Table 2'; and the main-text paragraph refers to 'Table 3' where Table 2 is evidently meant. These should be reconciled.","section":"Figure and table cross-references"},{"comment":"The acronym expansion is inconsistent: the abstract defines METS as 'Modulated Electrothermal Sensing' while the Introduction defines it as 'Multi-harmonic Electro-Thermal Spectroscopy'; the header title of the manuscript also differs from the arXiv title. The terminology should be unified.","section":"Abstract and Introduction"},{"comment":"The manuscript states that data and MATLAB code are available 'upon request'; for a measurement technique whose central claims rest on non-unique fitting, depositing the fitting code and representative raw spectra in a public repository would substantially strengthen the paper and is recommended.","section":"Data and Code Availability"},{"comment":"Because the R_CT/R_SEI separation is claimed to rest on the sub-quadratic current scaling of the kinetic heat, the authors should add a plot of the 2ω temperature amplitude normalized by I0² against I0² (or against a dimensionless overpotential) for the three current amplitudes; the present presentation cannot visually demonstrate the effect on which the separation claim depends.","section":"Figures 5 and S12"}],"recommendation":"major_revision","confidential_remarks":"The refereed identifiability concern is confirmed by the manuscript itself: the Figure 6 caption, the 0.5 ± 0.88 Ω uncertainty, the identical R_CT values at both electrodes in every cell, and the explicit 'assuming a small charge-transfer resistance (0.2 Ω)' in SI §12 together show that the four-component 2ω decomposition is not measured. If the authors retain the four-component claim unchanged, I would recommend rejection; a major revision that reframes the 2ω results as per-interface total interfacial resistance with R_CT as an upper bound, and that honestly reports the per-interface EIS discrepancy at the NMC anode, would make the paper publishable. The 1ω entropy results are, in my view, the more novel and better-supported contribution. The identical imposed R_CT values also suggest the fitting code should be inspected; I would recommend the editor obtain the code during revision."},"author_rebuttal":null,"desk_editor":{"model":"deepseek-v4-flash","letter":"Dear colleague,\n\nQuick take: METS is a real step forward, but only part of the abstract survives contact with the paper. The 1ω entropy measurement is the genuinely new capability: thermal-wave penetration depth lets you read the entropic coefficient at the near and far electrode separately, in an operating cell. That result is internally consistent (the symmetric cell sees equal-and-opposite signals; the NMC-graphite cell gives anode and cathode values from both sides that agree with literature) and it is independently validated by the heater-test of the thermal model. The 2ω total interfacial resistance also lands in the right place: the METS sums match EIS total resistances in the symmetric, NMC-Li, and electrodeposited-foil cells. That part of the paper deserves a serious referee.\n\nThe soft spot is the claimed 2ω decomposition into charge-transfer vs transport resistance. The paper's own sensitivity plots (Fig. 6c,d) say the 2ω signal is not very sensitive to exchange current density — i.e., to R_CT — at either interface. With the reported R_CT values (0.2–0.5 Ω) and currents (12–22 mA), the overpotential is ~10 mV, solidly in the linear Butler-Volmer regime, where kinetic heating scales as I² exactly like Ohmic heating, so varying current amplitude cannot separate the two. The reported uncertainties confirm the problem: symmetric-cell R_CT = 0.5 ± 0.88 Ω (the uncertainty exceeds the estimate), and the SI multilayer analysis explicitly imposes a 0.2 Ω charge-transfer resistance. So the four-component resistance table is not a measurement; it is a model prior. If true R_CT were non-negligible, the fitted transport resistances would shift. The abstract and introduction claim \"resolution of the overall interfacial impedance into charge-transfer and interface transport resistance components\" — that sentence should be softened until the identifiability problem is addressed.\n\nA second, smaller issue: post-SEI, METS total resistance (35.8 ± 6.28 Ω) exceeds the EIS total (26.9 ± 2.7 Ω) by more than the combined uncertainty, and the discrepancy is not discussed. And data/code are only \"available upon request,\" which for a fitting-heavy method is a reproducibility weakness.\n\nBottom line: the 1ω depth-resolved entropy and the total 2ω interfacial resistance are solid; the R_CT/transport split is not established. This paper deserves peer review — a good referee would push for reframing or removing the CT decomposition (or a redesign that actually achieves sensitivity), depositing code/data, and explaining the post-SEI mismatch. I'd bring it to reading group, and I'd cite the entropy part.\n\nRecommendation: send to review, conditionally.","headline":"The depth-resolved 1ω entropy measurement is credible and new, but the paper's headline 2ω claim — separating charge-transfer from transport resistance — is not supported by its own sensitivity analysis.","tokens_in":33106,"tokens_out":3125,"would_cite":true,"duration_ms":31671,"reading_group":"yes","serious_thinker":"yes","would_accept_peer_review":true},"rs_alignment":null,"lean_confirmation":null,"pith_extraction":{"msc":[],"pacs":["82.47.Aa"],"model":"deepseek-v4-flash","headline":"Thermal ripples from electrochemical heat reveal what happens at each electrode inside a working battery.","keywords":["METS","multi-harmonic electro-thermal spectroscopy","thermal penetration depth","solvation entropy","charge-transfer resistance","solid-electrolyte interphase","operando characterization","lithium-ion batteries"],"falsifier":"A direct test would be two otherwise identical symmetric cells whose exchange current density differs by an order of magnitude, for example through different electrolyte additives, while their SEI transport resistance is the same. If METS $2\\omega$ spectra fitted with a small imposed charge-transfer resistance return the same transport resistance in both cells while independent measurements confirm the kinetic difference, the separation holds; if the fitted transport resistance shifts when only kinetics changes, the charge-transfer/transport split is not valid.","tokens_in":31929,"feed_emoji":"🔋","tokens_out":9184,"duration_ms":95733,"temperature":0.7,"pith_summary":"This paper claims that the heat a lithium-ion cell produces while an alternating current passes through it can be turned into a depth-resolved, operando probe of each electrode-electrolyte interface. By measuring the resulting temperature oscillations at the first and second harmonics of the current, the authors recover the solvation entropy, interfacial transport resistance, charge-transfer resistance, and SEI resistance separately for the two electrodes in practical cells. This matters because conventional impedance or voltage measurements average over the whole cell or require symmetry assumptions, so they cannot tell which electrode is degrading or how much of the interfacial impedance is transport versus kinetics. The paper demonstrates the method on lithium symmetric, NMC-lithium, and a cell with electrodeposited and foil lithium electrodes, and shows operando SEI growth at one interface.","feed_headline":"Thermal waves measure each battery interface while the cell runs","feed_subtitle":"METS reads milli-Kelvin heat ripples to split impedance into transport and charge transfer at each electrode.","key_machinery":"Multi-harmonic Electro-Thermal Spectroscopy (METS) uses the thermal penetration depth $\\delta = \\sqrt{\\alpha/\\omega}$ as the depth selector and the harmonic order plus current-amplitude scaling as the process selector. Entropic heat at $1\\omega$ is measured at high frequencies where only the near-sensor interface contributes, and then at lower frequencies where the second interface contributes; $2\\omega$ heat from transport (ohmic, current-squared) and charge transfer (nonlinear, weaker than current-squared) is measured at several current amplitudes to separate the two. Feldman's algorithm for periodic heating in a stratified medium converts the computed heat-generation rates into the surface temperature spectrum that is fitted to the lock-in thermometry data.","core_discovery":"The central claim is that electrochemical heat sources carry enough information to serve as spatially resolved sensors of their own interfaces. Reversible solvation heat is proportional to current and appears at the first harmonic, while irreversible Ohmic heat from SEI/CEI transport is proportional to current squared and appears at the second harmonic; the nonlinear Butler-Volmer overpotential adds a second-harmonic heat component whose current scaling differs from a pure square law. Because a thermal wave at angular frequency $\\omega$ decays over penetration depth $\\delta = \\sqrt{\\alpha/\\omega}$, high-frequency signatures come only from the interface nearest the sensor and low-frequency signatures include both interfaces. Fitting the measured in-phase and out-of-phase temperature spectra with a layered heat-diffusion model yields the entropic coefficient at each interface and splits the total interfacial impedance into transport and charge-transfer parts. The authors validate the totals against EIS and demonstrate that two chemically similar lithium electrodes can have very different transport resistances, and that SEI growth can be tracked in real time.","pith_inferences":["If METS is as local as it appears, it could become an early failure-localization tool: a sensor on a cell tab might flag which electrode first develops high SEI resistance or plating-related heating before the cell's global impedance changes, a diagnostic the paper does not demonstrate.","The same harmonic-separation logic could be pushed to lower frequencies to capture mass-transport heat, which the authors leave for future work, potentially yielding depth-resolved diffusion properties rather than only resistances.","A decisive extension would be to vary exchange current density on purpose, for example with additives or temperature, and check whether METS recovers the expected kinetic change; the paper reports charge-transfer values that are small and effectively imposed in the fits."],"forward_implications":["METS can assign the overlapping semicircles of an EIS spectrum to a specific electrode and split each into transport and charge-transfer resistance without assuming equal electrodes.","SEI resistance at an individual lithium-electrolyte interface can be followed operando; after cycling at 40 °C, the foil electrode's transport resistance grew from 15.75 $\\Omega$ to 32.6 $\\Omega$, while the electrodeposited electrode's grew from 1.35 $\\Omega$ to 3.26 $\\Omega$.","Solvation entropy can be measured at the cathode and anode separately inside a working cell, not only as a cell-averaged or symmetric-cell quantity.","Because the heat signatures are electrochemical rather than structural, the approach applies to other battery chemistries and to arbitrary sensor positions within multilayer stacks."],"supporting_citations":[{"why":"Supplies Feldman's layered heat-diffusion solution used to convert heat-generation rates into the surface temperature spectrum.","marker":"[29]"},{"why":"Gives the reference Li-ion solvation entropic coefficient used to validate the 1ω METS result.","marker":"[7]"},{"why":"Gives an independent single-electrode entropic coefficient measurement used as a second validation point.","marker":"[34]"},{"why":"Provides the expected cathode entropic coefficients for NMC cells against which the depth-resolved values are checked.","marker":"[41]"},{"why":"Establishes the thermal-wave penetration-depth approach for operando spatial mapping and supplies thermal properties of cell layers.","marker":"[22]"},{"why":"Provides the Butler-Volmer kinetic relation used to model nonlinear charge-transfer heat and separate it from ohmic transport heat.","marker":"[43]"},{"why":"Supplies the EIS modeling basis for identifying electrolyte resistance and the semicircle ambiguity that METS resolves.","marker":"[40]"},{"why":"Provides the basis for EIS's inability to resolve similar-capacitance interfaces, the ambiguity METS removes.","marker":"[45]"}],"fun_headline_variants":["Thermal waves measure each battery layer while running","Heat waves probe battery interfaces with few-micron depth","METS uses heat ripples to split battery impedance per interface","Depth-resolved battery impedance from thermal waves","Battery interface kinetics decoded from thermal waves"],"cache_read_input_tokens":3200,"weakest_assumption_plain":"The load-bearing premise is that the charge-transfer resistance is small enough that the second-harmonic signal is insensitive to it: the reported charge-transfer values are imposed rather than measured, so if real kinetics were slow, the transport resistances fitted from the same spectra would be wrong.","fun_headline_variants_meta":{"raw":{"variants":["Thermal waves measure each battery layer while running","Heat waves probe battery interfaces with few-micron depth","METS uses heat ripples to split battery impedance per interface","Depth-resolved battery impedance from thermal waves","Battery interface kinetics decoded from thermal waves"]},"model":"deepseek-v4-flash","effort":"low","cost_usd":0.000692,"raw_usage":{"total_tokens":3163,"prompt_tokens":1008,"completion_tokens":2155,"prompt_tokens_details":{"cached_tokens":384},"prompt_cache_hit_tokens":384,"prompt_cache_miss_tokens":624,"completion_tokens_details":{"reasoning_tokens":2081}},"tokens_in":624,"tokens_out":2155,"duration_ms":14365,"temperature":1.0,"reasoning_tokens":2081,"cache_read_input_tokens":384,"cache_creation_input_tokens":0},"cache_creation_input_tokens":0},"created_at":"2026-08-12T19:09:20.394450+00:00","model_set":{"reader":"deepseek-v4-flash"},"falsifier":"A direct test would be two otherwise identical symmetric cells whose exchange current density differs by an order of magnitude, for example through different electrolyte additives, while their SEI transport resistance is the same. If METS $2\\omega$ spectra fitted with a small imposed charge-transfer resistance return the same transport resistance in both cells while independent measurements confirm the kinetic difference, the separation holds; if the fitted transport resistance shifts when only kinetics changes, the charge-transfer/transport split is not valid.","supporting_citations":[{"cited_title":"Algorithm for solutions of the thermal diffusion equation in a stratified medium with a modulated heating source,","cited_arxiv_id":null,"evidence_quote":"Supplies Feldman's layered heat-diffusion solution used to convert heat-generation rates into the surface temperature spectrum."},{"cited_title":"Correlating Li-Ion Solvation Structures and Electrode Potential Temperature Coefficients,","cited_arxiv_id":null,"evidence_quote":"Gives the reference Li-ion solvation entropic coefficient used to validate the 1ω METS result."},{"cited_title":"Ionic Peltier Effect in Li-Ion Electrolytes,","cited_arxiv_id":null,"evidence_quote":"Gives an independent single-electrode entropic coefficient measurement used as a second validation point."},{"cited_title":"Heat of Mixing During Fast Charge/Discharge of a Li-Ion Cell: A Study on NMC523 Cathode,","cited_arxiv_id":null,"evidence_quote":"Provides the expected cathode entropic coefficients for NMC cells against which the depth-resolved values are checked."},{"cited_title":"The Effect of Interfacial Deformation on Electrodeposition Kinetics,","cited_arxiv_id":null,"evidence_quote":"Provides the Butler-Volmer kinetic relation used to model nonlinear charge-transfer heat and separate it from ohmic transport heat."},{"cited_title":"Electrochemical Impedance Spectroscopy,","cited_arxiv_id":null,"evidence_quote":"Provides the basis for EIS's inability to resolve similar-capacitance interfaces, the ambiguity METS removes."}],"review_version":1}