Improving thermal conduction across cathode/electrolyte interfaces in solid-state lithium-ion batteries by hierarchical hydrogen-bond network

JL He and L Zhang and L Liu, MATERIALS & DESIGN, 194, 108927 (2020).

DOI: 10.1016/j.matdes.2020.108927

Effective thermal management is an important issue to ensure safety and performance of lithium-ion batteries. Fast heat removal is highly desired but has been obstructed by the high thermal resistance across cathode/electrolyte interface. In this study, self-assembled monolayers (SAMs) are used as the vibrational mediator to tune interfacial thermal conductance between an electrode, lithium cobalt oxide (LCO), and a solid state electrolyte, polyethylene oxide (PEO). Embedded at the LCO/PEO interface, SAMs are specially designed to form hierarchical hydrogen-bond (H-bond) network with PEO. Molecular dynamics simulations demonstrate that all SAMdecorated interfaces show enhanced thermal conductance and dominated by H-bonds types. The incorporation of poly(acrylic acid) (PAA) SAMdrastically enhances interfacial thermal conductance by approximately 211.69%, largely due to the formation of a strong H-bond, -COOH center dot center dot center dot:O, between PAA and PEO. Even withweaker H-bonds such as -OH center dot center dot center dot:O, it still outperforms the pristine interface as well as interfaces decorated with non-H-bonded SAMs, e.g. PE. Such improvement is attributed to the unique hierarchical H-bond network at the interface, which removes discontinuities in temperature field, straighten SAM chains, make materials strongly adhere, and couple the vibrational modes of materials. The study is expected to guide surface engineering for more effective thermal management in lithium-ion batteries. (C) 2020 Published by Elsevier Ltd.

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