Imperial College London

Prof Gregory Offer

Faculty of EngineeringDepartment of Mechanical Engineering

Professor in Electrochemical Engineering
 
 
 
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Contact

 

+44 (0)20 7594 7072gregory.offer Website

 
 
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Location

 

720City and Guilds BuildingSouth Kensington Campus

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Summary

 

Publications

Citation

BibTex format

@article{Zhang:2017:10.1149/2.0011801jes,
author = {Zhang, T and Marinescu, M and Walus, S and Kovacik, P and Offer, GJ},
doi = {10.1149/2.0011801jes},
journal = {Journal of the Electrochemical Society},
pages = {A6001--A6004},
title = {What Limits the Rate Capability of Li-S Batteries during Discharge: Charge Transfer or Mass Transfer?},
url = {http://dx.doi.org/10.1149/2.0011801jes},
volume = {165},
year = {2017}
}

RIS format (EndNote, RefMan)

TY  - JOUR
AB - Li-S batteries exhibit poor rate capability under lean electrolyte conditions required for achieving high practical energy densities. In this contribution, we argue that the rate capability of commercially-viable Li-S batteries is mainly limited by mass transfer rather than charge transfer during discharge. We first present experimental evidence showing that the charge-transfer resistance of Li-S batteries and hence the cathode surface covered by Li2S are proportional to the state-of-charge (SoC) and not to the current, directly contradicting previous theories. We further demonstrate that the observed Li-S behaviors for different discharge rates are qualitatively captured by a zero-dimensional Li-S model with transport-limited reaction currents. This is the first Li-S model to also reproduce the characteristic overshoot in voltage at the beginning of charge, suggesting its cause is the increase in charge transfer resistance brought by Li2S precipitation.
AU - Zhang,T
AU - Marinescu,M
AU - Walus,S
AU - Kovacik,P
AU - Offer,GJ
DO - 10.1149/2.0011801jes
EP - 6004
PY - 2017///
SN - 0013-4651
SP - 6001
TI - What Limits the Rate Capability of Li-S Batteries during Discharge: Charge Transfer or Mass Transfer?
T2 - Journal of the Electrochemical Society
UR - http://dx.doi.org/10.1149/2.0011801jes
UR - http://hdl.handle.net/10044/1/50416
VL - 165
ER -