Interfacial Thermal Conductance between Cu and Diamond with Interconnected W−W₂C Interlayer

Abstract

Manipulating the interfacial structure is vital to enhancing the interfacial thermal conductance (G) in Cu/diamond composites for promising thermal management applications. An interconnected interlayer is frequently observed in Cu/diamond composites; however, the G between Cu and diamond with an interconnected interlayer has not been addressed so far and thus is attracting extensive attention in the field. In this study, we designed three kinds of interlayers between a Cu film and a diamond substrate by magnetron sputtering coupled with heat treatment, including a W interlayer, an interconnected W–W2C interlayer, and a W2C interlayer, to comparatively elucidate the relationship between the interfacial structure and the interfacial thermal conductance. For the first time, we experimentally measured the G between Cu and diamond with an interconnected interlayer by a time-domain thermoreflectance technique. The Cu/W–W2C/diamond structure exhibits an intermediate G value of 25.8 MW/m2 K, higher than the 19.9 MW/m2 K value for the Cu/W2C/diamond structure and lower than the 29.4 MW/m2 K value for the Cu/W/diamond structure. The molecular dynamics simulations show that the G of the individual W2C/diamond interface is much higher than those of the individual Cu/diamond and W/diamond interfaces and W2C could reduce the vibrational mismatch between Cu and diamond; however, the G of the Cu/W2C/diamond structure is reduced by the lower thermal conductivity of W2C. This study provides insights into the relationship between the interconnected interfacial structure and the G between Cu and diamond and offers guidance for interface design to improve the thermal conductivity in Cu/diamond composites.

Single‐Atom‐Regulated Heterostructure of Binary Nanosheets to Enable Dendrite‐Free and Kinetics‐Enhanced Li–S Batteries

“…In addition, the responsivity of peak current and area of Li 2 S precipitation are crucial indexes to assess the electrochemical activity of solid–liquid transformation of polysulfides. [ 5b,27b ] Specifically, the responsivity of Li 2 S nucleation in Pt SAs/In 2 S 3 /Ti 3 C 2 (Figure 4g) is earlier than those in Super P, In 2 S 3 , Ti 3 C 2 , and In 2 S 3 /Ti 3 C 2 . Those observations demonstrate that Pt SAs/In 2 S 3 /Ti 3 C 2 possesses fast catalytic kinetics of Li 2 S nucleation and precipitation processes.…”

“…The unique LiPSs adsorption capability of Pt SAs/In 2 S 3 /Ti 3 C 2 should be from its hierarchical porous structure (Figure S14a, Supporting Information) and the unique adsorption sites between Pt SAs/In 2 S 3 /Ti 3 C 2 and polysulfides. [ 5b,25 ] The interaction between the Pt SAs/In 2 S 3 /Ti 3 C 2 @PP and LiPSs was further investigated by XPS. As exhibited in FigureS14b, Supporting Information, the S 2p spectrum of Li 2 S 6 shows two peaks at 161.4 and 162.8 eV, corresponding to the terminal (ST –1 ) and bridging (SB 0 ) sulfur.…”

“…Further, upon the adsorption of Li 2 S 6 , a significant upshift toward higher binding energy can be observed in Pt SAs/In 2 S 3 /Ti 3 C 2 , demonstrating its higher chemical anchoring affinity to LiPSs. [ 5b ] Furthermore, the two additional peaks centered at higher binding energy area of 168.9 and 167.2 eV are assigned to polythionate and thiosulfate, respectively. Meanwhile, both In 3d and Pt 4f peaks of Pt SAs/In 2 S 3 /Ti 3 C 2 ‐Li 2 S 6 shift toward lower binding energy (Figure 4c; Figure S14c, Supporting Information), demonstrating the increased electron density at the metal center and the strong chemical capture capability.…”

“…In addition, the Pt SAs/In 2 S 3 / Ti 3 C 2 @PP based cell exhibits the earliest cathodic peaks located at 2.32 V (peak I) and 2.02 V (peak II) and anodic peaks potentials of 2.38 V (peak IV) and 2.35 (peak III), which are assigned to the reduction of S 8 to high soluble LiPSs, Li 2 S 4 to insoluble species (Li 2 S 2 /Li 2 S), and the reverse process, respectively. [ 5b,31 ] From another perspective, [ 5b,32 ] different from the four control samples, the cell with Pt SAs/In 2 S 3 /Ti 3 C 2 @PP delivers the highest onset potentials of cathodic peaks and the lowest onset potentials of anodic peaks (Figure S19b–f and Table S4, Supporting Information), demonstrating the accelerated polysulfides redox kinetics by Pt SAs/In 2 S 3 /Ti 3 C 2 and the dramatic enhancement of the conversion efficiency of liquid–solid polysulfides. Figure S20, Supporting Information, illustrates the CV curves for initial five charges/discharges of Li–S batteries with different PP‐modified separators at a scan rate of 0.1 mV s −1 .…”

“…[ 4 ] In particular, the coating of functional materials on the separator stands out for its complementary countermeasure to suppress LiPSs shuttle effect and to regulate lithium dendrite growth. [ 5 ]…”