Identifying the Bottleneck for Heat Transport in Metal-Organic Frameworks

TL;DR

This study uses molecular dynamics simulations to identify interfaces between metal nodes and organic linkers as the main bottlenecks for heat transport in metal-organic frameworks, providing insights for tuning thermal conductivity.

Contribution

It reveals the primary bottleneck for heat conduction in MOFs and demonstrates how modifying bonding strength and metal mass can optimize thermal transport.

Findings

Interfaces are the main bottlenecks for heat conduction.

Changing bonding strength affects thermal conductivity.

Metal atom mass influences heat transport.

Abstract

Controlling the transport of thermal energy is key to most applications of metal-organic frameworks. Analyzing the evolution of the effective local temperature, the interfaces between the metal nodes and the organic linkers are identified as the primary bottlenecks for heat conduction. Consequently, changing the bonding strength at that node-linker interface and the mass of the metal atoms can be exploited to tune the thermal conductivity. This insight is generated employing molecular dynamics simulations in conjunction with advanced, ab initio parametrized force fields. The focus of the present study is on MOF-5 as a prototypical example of an isoreticular MOF. Still, the key findings prevail for different node structures and node-linker bonding chemistries. The presented results lay the foundation for developing detailed structure-to-property relationships for thermal transport in MOFs with the goal of devising strategies for the application-specific optimization of heat conduction.