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The Effect of Interfacial Charge Distribution on Chemical Compatibility and Stability of the High Voltage Electrodes (LiCoPO 4 , LiNiPO 4 )/Solid Electrolyte (LiPON) Interface
Author(s) -
Cherkashinin Gennady,
Yu Zhihang,
Eilhardt Robert,
Alff Lambert,
Jaegermann Wolfram
Publication year - 2020
Publication title -
advanced materials interfaces
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.671
H-Index - 65
ISSN - 2196-7350
DOI - 10.1002/admi.202000276
Subject(s) - electrolyte , materials science , cathode , electrochemistry , electrode , band bending , energy storage , chemical engineering , analytical chemistry (journal) , chemical physics , optoelectronics , chemistry , thermodynamics , power (physics) , physics , chromatography , engineering
Solid electrolytes hold the promise of improved safety and superior electrochemical stability in energy storage systems. Among those, electrolytes with phosphate anions are expected to be more stable at high operating voltages, thereby providing even higher energy density. The key challenge is to control the boundary conditions at the cathode/electrolyte interface, which impact drastically the functionality of the energy storage devices. Here, the evolution of the chemical composition and electronic properties of the interface forms upon consequent deposition of solid electrolyte (lithium phosphorous oxynitride [LiPON]) onto the 5 V LiCoPO 4 and LiNiPO 4 carbon‐free thin film cathode materials is in situ studied by comprehensive electron spectroscopy experiments combined with the energy band diagram approach. It is demonstrated that the driving forces for interfacial reactivity are the band bending direction and the double layer potential drop at the electrode–electrolyte interface coupled to an unfavorable electrochemical potential shift of involved electronic states upon contact formation. The probability for interfacial chemical reactions is essentially increased at small energy differences in the ionization potentials of the cathode material and electrolyte, whereas a large energy difference ensures their chemical compatibility.