This review article presents a survey of the literature on pulsed laser deposited thin film materials used in devices for energy storage and conversion, i.e., lithium microbatteries, supercapacitors, and electrochromic displays. Three classes of materials are considered: Positive electrode materials (cathodes), solid electrolytes, and negative electrode materials (anodes). The growth conditions and electrochemical properties are presented for each material and state-of-the-art of lithium microbatteries are also reported.

https://www.mdpi.com/2079-6412/9/6/386/pdf

Pulsed Laser Deposited Films for Microbatteries

This review discusses the contribution of physical vapor deposition (PVD) processes to the development of electrochemical energy storage systems with emphasis on solid-state batteries. A brief overview of different PVD technologies and details highlighting the utility of PVD for the fabrication and characterization of individual battery materials are provided. In this context, the key methods that have been developed for the fabrication of solid electrolytes and active electrode materials with well-defined properties are described, and demonstrations of how these techniques facilitate the in-depth understanding of fundamental material properties and interfacial phenomena as well as the development of new materials are provided. Beyond the discussion of single components and interfaces, the progress on the device scale is also presented. State-of-the-art solid-state batteries, both academic and commercial types, are assessed in view of energy and power density as well as long-term stability. Finally, recent efforts to improve the power and energy density through the development of 3D-structured cells and the investigation of bulk cells are discussed.

https://onlinelibrary.wiley.com/doi/pdf/10.1002/advs.202002044

Physical Vapor Deposition in Solid-State Battery Development: From Materials to Devices.

All-solid-state thin film lithium batteries (TFBs) are proposed as the ideal power sources for microelectronic devices. However, the high-temperature (>500 °C) annealing process of cathode films, such as LiCoO2 and LiMn2 O4, restricts the on-chip integration and potential applications of TFBs. Herein, tunnel structured Lix MnO2 nanosheet arrays are fabricated as 3D cathode for TFBs by a facile electrolyte Li+ ion infusion method at very low temperature of 180 °C. Featuring an interesting tunnel intergrowth structure consisting of alternating 1 × 3 and 1 × 2 tunnels, the Lix MnO2 cathode shows high specific capacity with good structural stability between 2.0 and 4.3 V (vs. Li+ /Li). By utilizing the 3D Lix MnO2 cathode, all-solid-state Lix MnO2 /LiPON/Li TFB (3DLMO-TFB) has been successfully constructed with prominent advantages of greatly enriched cathode/electrolyte interface and shortened Li+ diffusion length in the 3D structure. Consequently, the 3DLMO-TFB device exhibits large specific capacity (185 mAh g-1 at 50 mA g-1 ), good rate performance, and excellent cycle performance (81.3% capacity retention after 1000 cycles), outperforming the TFBs using spinel LiMn2 O4 thin film cathodes fabricated at high temperature. Importantly, the low-temperature preparation of high-performance cathode film enables the fabrication of TFBs on various rigid and flexible substrates, which could greatly expand their potential applications in microelectronics.

Tunnel Intergrowth Li x MnO 2 Nanosheet Arrays as 3D Cathode for High-Performance All-Solid-State Thin Film Lithium Microbatteries.

Electrochemical impedance spectroscopy (EIS) and complex nonlinear least squares (CNLS) analysis with an equivalent circuit (EqC) has been the standard research tool in Solid State Electrochemistry for many decades. With an ever increasing interest in the development of energy related materials with complex structures, the impedance spectra are becoming too complex for a simple CNLS-analysis. Inversion of the data from the frequency domain to a distribution function of relaxation times (DFRT), i.e. the τ-domain, has shown to present a better separation and visualization of the underlying electrochemical processes. These are presented by peaks with characteristic time constants that are associated with the separate processes. Hence, the interest in EIS-analysis with inversion to a DFRT has rapidly gained attention over the last decennia. In this contribution a brief review of the applications and limitations of the DFRT procedure is presented. Some examples from the field of solid oxide fuel cells (SOFC) and Li-ion based battery research are discussed. When possible a comparison is made between the exact DFRT (derived from known DFRT expressions) and three inversion methods: Fourier Transform (FT), Tikhonov Regularization and a recently developed multi-(RQ) CNLS-fit: 'm(RQ)fit'. It is shown that the three differently derived DFRT's can differ significantly, while the impedances reconstructed from the DFRT with the inverse process show a quite good match with the original data.

https://robots.iopscience.iop.org/article/10.1088/2515-7655/aba9e0/pdf

Distribution (function) of relaxation times, successor to complex nonlinear least squares analysis of electrochemical impedance spectroscopy?

The improved performance of spinel LiMn2O4 cathode with micro-nanostructured sphere-interconnected-tube morphology and surface orientation at extreme conditions for lithium-ion batteries

A promising cathode material for rechargeable batteries is LiMn2O4, which exhibits higher operating voltage, reduced toxicity and lower costs as compared to commonly used LiCoO2 cathodes. However, LiMn2O4 suffers from limited cycle life, as excessive capacity fading occurs during battery cycling due to dissolution of Mn into the acidic electrolyte. Here, we show that by structural engineering of stable, epitaxial LiMn2O4 thin films the electrochemical properties can be enhanced as compared to polycrystalline samples. Control of the specific crystal orientation of the LiMn2O4 thin films resulted in dramatic differences in surface morphology with pyramidal, rooftop or flat features for respectively (100), (110), and (111) orientations. All three types of LiMn2O4 films expose predominantly  ⟨111⟩ crystal facets, which is the lowest energy state surface for this spinel structure. The (100)-oriented LiMn2O4 films exhibited the highest capacities and (dis)charging rates up to 33C, and good cyclability over a th...

/pdf/enhanced-lithium-transport-by-control-of-crystal-orientation-2a3jh4mi3n.pdf

Ron Hendriks

Papers

Enhanced Lithium Transport by Control of Crystal Orientation in Spinel LiMn2O4 Thin Film Cathodes