Multi-scale molecular model application

This section deals with multi-scale models for the PEFC and consists of three subsections, 4.1,4.2, and 4.3, that relate to molecular-level models, bridging models between scales and device/process level models, respectively. The objectives of these subsections are to survey the development and application of these models. 

In the following, the key issues and related models at different scales in PEMFCs are outlined in Section 3.2. In Section 3.3, the multi-scale strategies across neighboring scales are summarized and compared. The typical applications based on coarse-grained molecular dynamics (CG-MD) method areal so exhibited to discuss the multi-scale modeling techniques in PEMFC. However, there are still some major challenges and limitations in these modeling and simulations, as summarized in Section 3.4. 

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