Peer review of: Electrode interface optimization advances conversion efficiency and stability of thermoelectric de  (2020)

Reviewers' comments: 
 
Reviewer #1 (Remarks to the Author): 
 
The paper on the "Electrode interface optimization for CoSb3-based Skutterudite thermoelectric 
devices.." ic certainly an interesting contribution to a suiccessful Skutterudite module fabrication. The 
paper is well documented, length and discussion are appropriate. There are a few items to be 
considered prior to publication: 
1) The manuscript need overhaul by a NATIVE ENGLISH SPEAKER (although it is well written in 
general, articles are missing and formulations need to be honed. 
2) The authors state "It has been widely observed experimentally that filler atoms in CoSb3-based 
filled SKD such as Yb,Ba et al. are not involved in the growth of the IRL". This is not true as we can 
simply track intermetallic compounds from databases such as: "Ba5{V,Nb}12Sb19+x, novel variants 
of the Ba5Ti12Sb19+x-type: Crystal structure and physical properties" in Phys. Chem. Chem. Phys. 
(2015) 17, 24248-24261 etc... 
3) Allthough thin layers are not prone to exert stess due to lattice parameter mismatch, no discussion 
was made on this topic although experimental data for the intermetallic layers NbSb2, NbSb2 exist. 
3)Fig 1b: Formation energies depicted are from the binary compound richest in Sb (such as NbSb2..) 
or from the thermodynamically most stable binary antimonide?? 
 
 
 
Reviewer #2 (Remarks to the Author): 
 
It is an interesting study to solve an overlooked area in thermoelectric system. However, tests have 
only been conducted for about 100 days, far shorter than real application scenario. Also test of 
constant thermal shock should also be conducted over long time. This type of study may fit basic 
materials science journal better. 
 
 
Reviewer #3 (Remarks to the Author): 
  
This manuscript proposed a criterion for screening barrier layer, used in thermoelectric devices, based 
on the combination of the moderately low interfacial reaction energy (EIR) and high migration energy 
barrier (EMig) of Sb through the formed interfacial reaction layer (IRL). It’s an interesting research 
work on making thermoelectric devices and meaningful to advance the application of TE techniques. 
However, I think the manuscript need major revision before consideration for publication, addressing 
problems such as the following: 
 
1. Were the interface studies done simply under heating? How does the current/ voltage kick in during 
service affect the chemical reaction and diffusion process? 
2. In page 8, statement of ‘when the IRL is thin, the growth of the IRL is controlled by chemical 
reaction described by the linear item in Eq. (1)’ seems to contradict with the following statement ‘after 
aging for about 50 hours, the time dependences of Nb joint aging at 923 K and Zr joint aging at 858 K 
demonstrate linear relation, indicating the diffusion control mechanism’. Why ? 
3. Double check the statement in line 210-212. The values of those constant for Zr case do not look 
reasonable. 
4. Since the resistivity of defect layer dominates the resistivity at the interfaces, does that mean 
inhibiting the consumption of Sb is actually the final goal here, which is determined by the steady 
state eventually achieved when the depletion of Sb is complete? In that case, how long will the steady 
state be achieved and is it long enough compared to the test duration here and to service duration 
required in the future? 
5. How does the temperature affect the chemical reaction and diffusion process and how was it 
reflected in the parameters such as EIR, EMig, and Formation Enthalpy? 
6. In figure S4, the original interfaces before aging test should be provided as references. Are there 
voids formed at SKD side near the interface?