TY - JOUR

T1 - Lithium Niobate for Fast Cycling in Li-ion Batteries: Review and New Experimental Results

AU - Hüger, Erwin

AU - Riedel, Lukas

AU - Zhu, Jing

AU - Stahn, Jochen

AU - Heitjans, Paul

AU - Schmidt, Harald

N1 - This work is based on experiments performed at the Swiss spallation neutron source SINQ, Paul Scherrer Institute, Villigen, Switzerland. We thank Lars Dörrer and Johanna Uhlendorf (TU Clausthal) for electrochemical cell construction, and handling with the LiNbO3 and LiAlO2 sputter targets, respectively. The Bruker Discover D8 HRXRD instrument was financially supported by the Deutsche Forschungsgemeinschaft in the framework of the INST 189/189-1 FUGG, which is gratefully acknowledged. The Gatan Ion Beam Coater (IBC 681) was financed by the DFG in the framework of the research unit FOR 1277 (‘molife’), which is gratefully acknowledged.

PY - 2023/4/25

Y1 - 2023/4/25

N2 - Li-Nb-O-based insertion layers between electrodes and electrolytes of Li-ion batteries (LIBs) are known to protect the electrodes and electrolytes from unwanted reactions and to enhance Li transport across interfaces. An improved operation of LIBs, including all-solid-state LIBs, is reached with Li-Nb-O-based insertion layers. This work reviews the suitability of polymorphic Li-Nb-O-based compounds (e.g., crystalline, amorphous, and mesoporous bulk materials and films produced by various methodologies) for LIB operation. The literature survey on the benefits of niobium-oxide-based materials for LIBs, and additional experimental results obtained from neutron scattering and electrochemical experiments on amorphous LiNbO 3 films are the focus of the present work. Neutron reflectometry reveals a higher porosity in ion-beam sputtered amorphous LiNbO 3 films (22% free volume) than in other metal oxide films such as amorphous LiAlO 2 (8% free volume). The higher porosity explains the higher Li diffusivity reported in the literature for amorphous LiNbO 3 films compared to other similar Li-metal oxides. The higher porosity is interpreted to be the reason for the better suitability of LiNbO 3 compared to other metal oxides for improved LIB operation. New results are presented on gravimetric and volumetric capacity, potential-resolved Li + uptake and release, pseudo-capacitive fractions, and Li diffusivities determined electrochemically during long-term cycling of LiNbO 3 film electrodes with thicknesses between 14 and 150 nm. The films allow long-term cycling even for fast cycling with rates of 240C possessing reversible capacities as high as 600 mAhg −1. Electrochemical impedance spectroscopy (EIS) shows that the film atomic network is stable during cycling. The Li diffusivity estimated from the rate capability experiments is considerably lower than that obtained by EIS but coincides with that from secondary ion mass spectrometry. The mostly pseudo-capacitive behavior of the LiNbO 3 films explains their ability of fast cycling. The results anticipate that amorphous LiNbO 3 layers also contribute to the capacity of positive (LiNi xMn yCo zO 2, NMC) and negative LIB electrode materials such as carbon and silicon. As an outlook, in addition to surface-engineering, the bulk-engineering of LIB electrodes may be possible with amorphous and porous LiNbO 3 for fast cycling with high reversible capacity.

AB - Li-Nb-O-based insertion layers between electrodes and electrolytes of Li-ion batteries (LIBs) are known to protect the electrodes and electrolytes from unwanted reactions and to enhance Li transport across interfaces. An improved operation of LIBs, including all-solid-state LIBs, is reached with Li-Nb-O-based insertion layers. This work reviews the suitability of polymorphic Li-Nb-O-based compounds (e.g., crystalline, amorphous, and mesoporous bulk materials and films produced by various methodologies) for LIB operation. The literature survey on the benefits of niobium-oxide-based materials for LIBs, and additional experimental results obtained from neutron scattering and electrochemical experiments on amorphous LiNbO 3 films are the focus of the present work. Neutron reflectometry reveals a higher porosity in ion-beam sputtered amorphous LiNbO 3 films (22% free volume) than in other metal oxide films such as amorphous LiAlO 2 (8% free volume). The higher porosity explains the higher Li diffusivity reported in the literature for amorphous LiNbO 3 films compared to other similar Li-metal oxides. The higher porosity is interpreted to be the reason for the better suitability of LiNbO 3 compared to other metal oxides for improved LIB operation. New results are presented on gravimetric and volumetric capacity, potential-resolved Li + uptake and release, pseudo-capacitive fractions, and Li diffusivities determined electrochemically during long-term cycling of LiNbO 3 film electrodes with thicknesses between 14 and 150 nm. The films allow long-term cycling even for fast cycling with rates of 240C possessing reversible capacities as high as 600 mAhg −1. Electrochemical impedance spectroscopy (EIS) shows that the film atomic network is stable during cycling. The Li diffusivity estimated from the rate capability experiments is considerably lower than that obtained by EIS but coincides with that from secondary ion mass spectrometry. The mostly pseudo-capacitive behavior of the LiNbO 3 films explains their ability of fast cycling. The results anticipate that amorphous LiNbO 3 layers also contribute to the capacity of positive (LiNi xMn yCo zO 2, NMC) and negative LIB electrode materials such as carbon and silicon. As an outlook, in addition to surface-engineering, the bulk-engineering of LIB electrodes may be possible with amorphous and porous LiNbO 3 for fast cycling with high reversible capacity.

KW - diffusivity

KW - gravimetric and volumetric capacity

KW - lithium ion battery

KW - lithium niobate

KW - long-term cycling

KW - mass density

KW - neutron reflectometry

KW - porosity

KW - rate capability

KW - supercapacitor

UR - http://www.scopus.com/inward/record.url?scp=85160204344&partnerID=8YFLogxK

U2 - 10.3390/batteries9050244

DO - 10.3390/batteries9050244

M3 - Article

VL - 9

SP - 244

JO - Batteries

JF - Batteries

IS - 5

M1 - 244

ER -