Relating the 3D electrode morphology to Li-ion battery performance; a case for LiFePO&lt;sub&gt;4&lt;/sub&gt;

Liu, Zhao; Verhallen, T.W.; Singh, D.P.; Wang, Hongqian; Wagemaker, M.; Barnett, Scott

doi:10.1016/j.jpowsour.2016.05.097

Relating the 3D electrode morphology to Li-ion battery performance; a case for LiFePO₄

Title

Relating the 3D electrode morphology to Li-ion battery performance; a case for LiFePO₄

Author

Liu, Zhao (Northwestern University)
Verhallen, T.W. (TU Delft RST/Fundamental Aspects of Materials and Energy)
Singh, D.P. (TU Delft RST/Fundamental Aspects of Materials and Energy)
Wang, Hongqian (Northwestern University)
Wagemaker, M. (Northwestern University)
Barnett, Scott (Northwestern University)

Date

2016-08-30

Abstract

One of the main goals in lithium ion battery electrode design is to increase the power density. This requires insight in the relation between the complex heterogeneous microstructure existing of active material, conductive additive and electrolyte providing the required electronic and Li-ion transport. FIB-SEM is used to determine the three phase 3D morphology, and Li-ion concentration profiles obtained with Neutron Depth Profiling (NDP) are compared for two cases, conventional LiFePO₄ electrodes and better performing carbonate templated LiFePO₄ electrodes. This provides detailed understanding of the impact of key parameters such as the tortuosity for electron and Li-ion transport though the electrodes. The created hierarchical pore network of the templated electrodes, containing micron sized pores, appears to be effective only at high rate charge where electrolyte depletion is hindering fast discharge. Surprisingly the carbonate templating method results in a better electronic conductive CB network, enhancing the activity of LiFePO₄ near the electrolyte-electrode interface as directly observed with NDP, which in a large part is responsible for the improved rate performance both during charge and discharge. The results demonstrate that standard electrodes have a far from optimal charge transport network and that significantly improved electrode performance should be possible by engineering the microstructure.

Subject

3D imaging
Charge transport
Electrode morphology
FIB-SEM
Li-ion batteries
LiFePO
Neutron depth profiling

To reference this document use:

http://resolver.tudelft.nl/uuid:b4cce9d1-1cdb-49bb-950b-6627e2a18680

DOI

https://doi.org/10.1016/j.jpowsour.2016.05.097

Embargo date

2018-05-30

ISSN

0378-7753

Source

Journal of Power Sources, 324, 358-367