Co-sputtering of lithium vanadium oxide thin films with variable lithium content to enable advanced solid-state batteries

Abstract

Advanced solid-state batteries most likely will entail aggressive structures or architectures with constraints that typically limit processing temperatures. Considering this, we have identified the importance of providing lithiated electrode material...

Lithium Spatial Distribution and Split-Off Electronic Bands at Nanoscale V2O5/LiPON Interfaces

“…This high concentration of lithium and oxygen near the surface, followed by the sharp decrease in lithium and oxygen content, could be due to a reaction with air to form a thin layer of Li 2 O and/or Li 2 CO 3 on the sample surface. Previously, we observed a very strong and characteristic CL spectrum of Li 2 O powder, unlike the spectra in this study, so the formation of a lithium carbonate such as Li 2 CO 3 is more likely …”

“…Previously, we observed a very strong and characteristic CL spectrum of Li 2 O powder, unlike the spectra in this study, so the formation of a lithium carbonate such as Li 2 CO 3 is more likely. 58 After this near-surface region in the first ∼10 nm below the sample surface, the lithium concentration steadily increases to ∼2 Li per unit V 2 O 5 approximately 70 nm below the sample surface and remains relatively constant for deeper depths. These deviations are probably caused by the diffusion of Li to the bottom and top interfaces, where they can sit at defects or react with ambient air.…”

“…An additional LVO sample was lithiated through the simultaneous sputtering of V 2 O 5 (target power of 7.55 W/cm 2 ) and Li 2 O (target power of 4.45 W/cm 2 for approximately one Li insertion) on a similar substrate in a 100% Ar atmosphere. 58 This sample was prepared without a LiPON overlayer and used to compare depth profiles of Li content measured by XPS with depth profiles of conduction band densities of states measured by DRCLS. Between deposition and XPS, this uncoated sample was exposed to air for approximately 10 min during transfer.…”

Monolithically-stacked thin-film solid-state batteries

“…Several innovations are required: i) Depending on whether high energy or high power is desired, the cathode thickness must be increased to up to tens of μm; ii) The cathode must be crystallized to maximize capacity but without degradation of the other layers. This may be achieved by rapid thermal annealing, 30 photonic annealing methods, 31 or the use of cathodes such as vanadates with low annealing temperatures; 32 iii) The number of stacked cells must ideally be increased up to 10; iv) The development of stacked thin-film cells in an anode-free design, e.g., by thin seed layers of gold or carbon. 27,33 When all these points are met, we expect -11 -stacked thin-film batteries to reach specific energies >400 Wh•kg -1 and specific powers >10 kW•kg -1 .…”

Hierarchical structure promoted lithiation/delithiation behavior of a double-carbon microsphere supported nano-Co3O4 anode

“…As a result, electrode materials with high volumetric energy density and good chemical stability are highly appealing. In this regard, TMOs [1][2][3][4][5][6] have attracted a lot of attention owing to their abundant resources, low environmental hazards and more importantly high volumetric capacities based on a conversion reaction mechanism. Among them, Co 3 O 4 is considered a promising candidate owing to its capability of accommodating up to 8 Li + ions per formula unit, delivering a theoretical capacity of up to 3293 W h L −1 .…”