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Nonequilibrium Pathways during Electrochemical Phase Transformations in Single Crystals Revealed by Dynamic Chemical Imaging at Nanoscale Resolution
Author(s) -
Yu YoungSang,
Kim Chunjoong,
Liu Yijin,
van der Ven Anton,
Meng Ying Shirley,
Kostecki Robert,
Cabana Jordi
Publication year - 2015
Publication title -
advanced energy materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.08
H-Index - 220
eISSN - 1614-6840
pISSN - 1614-6832
DOI - 10.1002/aenm.201402040
Subject(s) - electrode , materials science , battery (electricity) , nanoscopic scale , particle (ecology) , electrochemistry , phase (matter) , chemical physics , nanotechnology , non equilibrium thermodynamics , thermodynamics , chemistry , power (physics) , physics , oceanography , organic chemistry , geology
The energy density of current batteries is limited by the practical capacity of the positive electrode, which is determined by the properties of the active material and its concentration in the composite electrode architecture. The observation in dynamic conditions of electrochemical transformations creates the opportunity of identifying design rules toward reaching the theoretical limits of battery electrodes. But these observations must occur during operation and at multiple scales. They are particularly critical at the single‐particle level, where incomplete reactions and failure are prone to occur. Here, operando full‐field transmission X‐ray microscopy is coupled with X‐ray spectroscopy to follow the chemical and microstructural evolution at the nanoscale of single crystals of Li 1+ x Mn 2– x O 4 , a technologically relevant Li‐ion battery electrode material. The onset and crystallographic directionality of a series of complex phase transitions are followed and correlated with particle fracture. The dynamic character of this study reveals the existence of nonequilibrium pathways where phases at substantially different potentials can coexist at short length scales. The results can be used to inform the engineering of particle morphologies and electrode architectures that bypass the issues observed here and lead to optimized battery electrode properties.