Commercial Li-ion Batteries Research Articles

Enhancing sodium-ion storage performance of MoO2/N-doped carbon through interfacial Mo-N-C bond

Na-ion batteries (SIBs) have attracted considerable attention as promising alternatives to commercial Li-ion batteries (LIBs) due to comparable redox potential, and natural abundance of Na. However, it remains challenging to explore suitable anodes for SIBs. Herein, a MoO2/N-doped carbon (MoO2/N-C) composite composed of MoO2 nanocrystals embedded within carbon matrix with a Mo-N-C chemical bond is prepared by a simple yet effective carbonization-induced topochemical transformation route. Na-ion half-cells using MoO2/N-C exhibit excellent cycling stability over 5000 cycles at 5 A g−1 and superior rate capability. Physicochemical characterizations and first principles density functional theory (DFT) simulations reveal that the formation of chemical bond at the interface between MoO2 and N-doped carbon plays an important role in the excellent charge storage properties of MoO2/N-C. More importantly, the interfacial coupling can efficiently promote interface charge transfer. Benefiting from this, Na-ion capacitors (SICs) constructed with the MoO2/N-C anode and activated carbon cathode can deliver an impressive energy density of 15 W h kg−1 at a power density of 1760 W kg−1, together with a capacitance retention of 92.4% over 1000 cycles at 10 A g−1. The proposed strategy in this paper based on interfacial chemical bond may hold pro mises for the design of high-performance electrodes for energy storage devices.

Experimental study on the crushing behaviour of lithium-ion battery modules

Lithium-ion (Li-ion) battery systems are used for electric vehicles (EV) in the automotive industry due to their lightweight and high energy density. The battery modules are composite structures with significant geometry and material non-linearity. Their behaviour under mechanical loading is important for EV performance and crashworthiness design. In this study, quasi-static (0.06 mm/s) and low speed (50 mm/s) crush tests were conducted on commercial vehicle Li-ion battery modules to study their response. Two steel impactors, namely, a 60° wedge and a hemispherical end punch were used to investigate the force-displacement-voltage responses of the modules. Based on the test data, the effect of loading and boundary conditions, i.e. crush velocity, the presence of a cover plate and shape of impactor on the overall response of the battery modules was analysed.

Solvated Ion Intercalation in Graphite: Sodium and Beyond.

Reversible intercalation of guest ions in graphite is the key feature utilized in modern battery technology. In particular, the capability of Li-ion insertion into graphite enabled the successful launch of commercial Li-ion batteries 30 years ago. On the road to explore graphite as a universal anode for post Li-ion batteries, the conventional intercalation chemistry is being revisited, and recent findings indicate that an alternative intercalation chemistry involving the insertion of solvated ions, designated as co-intercalation, could overcome some of the obstacles presented by the conventional intercalation of graphite. As an example, the intercalation of Na ions into graphite for Na-ion batteries has been perceived as being thermodynamically impossible; however, recent work has revealed that a large amount of Na ions can be reversibly inserted in graphite through solvated-Na-ion co-intercalation reactions. More recently, it has been extensively demonstrated that with appropriate electrolyte selection, not only Na ions but also other ions such as Li, K, Mg, and Ca ions can be co-intercalated into a graphite electrode, resulting in high capacities and power capabilities. The co-intercalation reaction shares a lot in common with the conventional intercalation chemistry but also differs in many respects, which has attracted tremendous research efforts in terms of both fundamentals and practical applications. Herein, we aim to review the progress made in understanding the solvated-ion intercalation mechanisms in graphite and to comprehensively summarize the state-of-the-art achievements by surveying the correlations among the guest ions, co-intercalation conditions, and electrochemical performance of batteries. In addition, the advantages and challenges related to the practical application of graphite undergoing co-intercalation reactions are presented.

Novel 3D Nanoporous Zn-Cu Alloy as Long-Life Anode toward High-Voltage Double Electrolyte Aqueous Zinc-Ion Batteries.

The recharge ability of zinc metal-based aqueous batteries is greatly limited by the zinc anode. The poor cycling durability of Zn anodes is attributed to the dendrite growth, shape change and passivation, but this issue has been ignored by using an excessive amount of Zn in the past. Herein, a 3D nanoporous (3D NP) Zn-Cu alloy is fabricated by a sample electrochemical-assisted annealing thermal method combined, which can be used directly as self-supported electrodes applied for renewable zinc-ion devices. The 3D NP architectures electrode offers high electron and ion transport paths and increased material loading per unit substrate area, which can uniformly deposit/strip Zn and improve charge storage ability. Benefiting from the intrinsic materials and architectures features, the 3D NP Zn-Cu alloy anode exhibits high areal capacity and excellent cycling stability. Further, the fabricated high-voltage double electrolyte aqueous Zn-Br2 battery can deliver maximum areal specific capacity of ≈1.56 mAh cm-2 , which is close to the level of typical commercial Li-ion batteries. The excellent performance makes it an ideal candidate for next-generation aqueous zinc-ion batteries.

In Operando Diffraction Radiography and Tomography on Li-Ion Batteries

Diffraction radiography and tomography were used to study different commercial Li-ion batteries. Depending on the data processing either 'direct' parameters, such as phase distributions, or more abstract, derived parameters, like degree of lithiation of the graphite anode or even local state of charge, can be extracted. Especially the lithium distribution is an interesting parameter and is surprisingly inhomogeneous throughout the volume of a commercial battery cell.

Optimization of Silicon-Graphite Anode and Polymeric Binders for Lithium-Ion Batteries

Graphite (G) is considered as the state-of-the-art anode material in commercial Li-ion batteries (LIBs), attributed due to its long cycle life, high Coulombic/energy efficiency and low cost. However, its low theoretical specific capacity (372 mAh g-1/ 840 mAh cm−3 for LiC6) is a limiting factor towards the large scale integration of emerging applications such as electromobility (electric vehicles, xEVs). Therefore, it is essential to search for other anode active materials with higher theoretical capacity.1 Silicon (Si) is one of the most appealing anode active materials with an extra-high capacity of 4200 mAh g-1 /9660 mAh cm−3 (Li4.4Si) and 3590 mAh g-1/8360 mAh cm−3 (Li3.75Si) at 415 oC and 25 oC respectively, suitable operating potential (0.2-0.4 V vs. Li/Li+), high abundancy (second abundant element in the earth crust) and thus low cost, superior safety and, environmental friendliness. However, in spite of all the resilient features, Si shows an extreme volume change ( ≥ 280%) upon (de-)lithiation, low electric conductivity, low initial Coulombic efficiency, electrode swelling and, electrolyte drying. These challenges limit the usage of Si in large-scale commercial LIBs. Many strategies have been suggested to overcome the above-mentioned difficulties, and two of the most promising strategies are: (1) use of Si-G composite anode active material, resulting in a synergistic beneficial effect of G and Si. The composite electrode shows longer cycle life and lower volume change with respect to Si anode and higher theoretical capacity compared to G anode. Moreover, G also enhances the electrical conductivity of the blended anode electrode. However, it is crucial to optimize the composition of the Si to G ratio so as to obtain desirable performances. (2) Use of new tailored binders for Si-based anodes. Binders are electrochemically inactive components of LIBs, nevertheless, they play a major role in the mechanical stability of the electrodes, irreversible capacity losses and stabilizing the cycling performance. Suitable binder for Si-based anodes should accommodate the volume change of Si particles. These binders usually contain carboxylate or imide functional groups, which interact strongly with the surface of the Si during charge/discharge of the battery.2 This implies also that the choice of binders for Si may not be necessarily the same as that of G.In this work, we have investigated and optimized the composition of Si-G composite anode using a mixture of state-of-the-art carboxymethyl cellulose (CMC) and poly (acrylic acid) (PAA) binders. Furthermore, the composition of the binders was optimized for the corresponding different ratio of the Si-G blends. Afterward, the benchmarked electrodes were further studied with different designer bio-polymeric binders such as chitosan, tragacanth gum, alginates, etc. The electrochemical properties (long-term cycling, rate capability, cyclic voltammetry,...) for the optimized Si to G ratio electrodes were investigated, followed by surface characterization and thermal reactivity.

Polymorphic Consideration in Conversion Reaction-Based Anode Materials for Next-Generation Li Rechargeable Batteries

Beginning with the commercialization by Sony in the 1990s, Li-ion batteries (LIBs) have been used in many electronic devices. In commercialized LIBs, insertion reaction-based electrode materials, such as LiCoO2, LiFePO4, LiMn2O4 for the cathode and graphite, Li4Ti5O12, TiO2 for the anode, have been dominantly used as active materials. In these materials, Li-ions can reversibly be stored and extracted at the specific interstitial site in the crystal without severely collapsing the initial crystal structure. As so, the crystallographic phase significantly affects the electrochemical performances because the local environments around the interstitial site are all different among these phases. For example, LiFePO4 has stable FePO4 framework even after most Li-ions have been extracted, although some Li-ions confined in the tunnel block the migration paths due to the one-dimensional tunnel inside the crystal. In contrast, Li-ions can move easier in LiCoO2 when comparing with LiFePO4 even if the Li-ions are trapped in the Li slab, but over lithiation results in the collapse of the layered structure leading to capacity fading. Even in the same composition, the electrochemical Li storage behavior varies much by the polymorphs. For instance, the layered LiCoO2 exhibit larger reversible capacity and higher redox potential compared to spinel structured Li2Co2O4 [1], and in case of TiO2, despite the similar amount of Li-ion storage, in detail, the voltage profiles are different in anatase, rutile and brookite TiO2 [2].Since the demand for high capacity energy storage devices is continuously growing, there have been extensive researches on high energy density electrode materials based on alloying and conversion reaction due to the limited capacity of insertion-based electrode materials. Manganese dioxide (MnO2) has been considered as a potential candidate due to its low cost, environmentally benignity and especially large theoretical capacity of ~1233 mAh g-1. Accordingly, various types of polymorphs in MnO2 (α, β, γ, δ, ε, λ, etc.) have been adopted as the anode materials in LIBs. However, unlike the insertion-based electrode, the effect of crystal structure in electrochemical conversion reaction was note clearly identified because it is hard to identify the detailed phase transition process as the initial crystalline structures transformed to the amorphous state after lithiation. Recently, some researchers compared the Li storage performance of different polymorphs of MnO2 [3,4], but the morphology of the materials are quite different or the reversible capacities are far below the theoretical value based on the conversion reaction, which could not sufficiently explain the polymorphic effects in conversion reaction. In this work, we have prepared 4 different polymorphs of MnO2 (α, β, Ramsdellite, and λ) in similar hollow urchin-like morphology and compared the Li storage behaviors to discover the influence of polymorphs in conversion-based electrode materials. Among those 4 polymorphs, λ-MnO2 exhibits the highest reversible capacity of ~1200 mAh g-1 and the fastest reaction kinetics. To demonstrate the structural advantages of λ-MnO2, we observed structural changes during electrochemical reactions using synchrotron-based X-ray absorption spectroscopy and X-ray crystallography. As a result, we discovered that the overall Li storage behaviors in the 4 different polymorphs are nearly the same, however, the structural similarity between the initial polymorphs and the final polymorph after reversible conversion reaction affects the electrochemical performance. More detailed discussion will be presented at the time of meeting.

Porous Silicon-Cobalt Silicide-Carbon Composites for Reversible Lithium Storage

With increasing use of portable electronic devices and electric vehicles, demand for development of high-energy density rechargeable batteries is rising. To meet the market demand for long-lasting rechargeable batteries, energy density of Li-ion batteries (LIBs) should be increased. The energy density of batteries is determined by the capacities of electrodes. Carbonaceous materials have been used as negative electrodes (anodes) in commercial LIBs because of their low operating potential and reasonable cycle life. However, the theoretical capacity of graphite anodes is relatively low, which is 372 mAh g-1 for the fully intercalated LiC6 phase. To increase the capacity, different types of materials using alloying or conversion reaction should be developed. Li-alloy-based materials can store several Li ions with an atom by electrochemical alloying reactions and therefore, high capacity can be obtained. In particular, Si has a high theoretical capacity of 3580 mAh g-1 for Li15Si4 and low operating potential. However, serious capacity fading usually occurs because of huge volume changes during cycling and their low electric conductivity. To address this problem, many strategies have been developed through changes in materials design. For example, incorporation of carbon is the most famous method to solve the capacity fading of Li-alloy-based materials upon cycling. The existence of carbon in Si matrix can buffer the volume expansion of Si materials with increased electric conductivity, thus simultaneously improving both cycling and rate performance. Porous structure can be another strategy to relieve the volume expansion by using the internal pores. However, the process is generally time and energy consuming. In this study, we report a simple preparation process of porous Si-CoSi2-C composites as anode materials for LIBs. The porous composite was synthesized through cheap starting materials and cost-effective methods. Si, magnesium silicide, and cobalt oxide were mixed using high energy mechanical milling (HEMM). Then, a carbon material was incorporated by HEMM. To produce porous structure, MgO formed by HEMM was removed by a wet etching process. As a result, porous Si-CoSi2-C composites were prepared. These composites exhibited a reversible capacity of 1100 mAh g-1 and good capacity retention after 100 cycles. The porous structure and the amorphous carbon matrix alleviated the volume change to allow the enhanced electrochemical performance.

High-temperature Aging Behavior of Commercial Li-Ion Batteries

High-temperature Aging Behavior of Commercial Li-Ion Batteries

Correlating Materials Degradation Trends to Electrochemical Indicators in Systematic Long-Term Cycling of Commercial Li-Ion Batteries

In order to improve the operation of Li-ion batteries the long-term performance is the subject of much research. Of particular importance is understanding systematic trends in degradation through a broad range of operating conditions. Over the course of the last few years, researchers at Sandia National Labs have conducted a systematic study of battery cycling behavior. In this study, dozens of commercial NCA (LiNixCoyAl1-x-yO2) and NMC (LiNixMnyCo1-x-yO2) cells were cycled to 80% capacity and end of life across a range of temperatures, discharge rates, and depth of discharge windows. Analysis of both in situelectrochemical data and postmortem materials degradation was done.During cycling, cell resistance (IR), Electrochemical Impedance Spectroscopy (EIS), and differential capacity (dQ/dV) experiments were conducted periodically. The data from these experiments were used to understand the state of health (SoH) of cycling cells, including SEI formation and Li plating, as well as general mass transport and kinetic properties.For the postmortem analysis cells in pristine condition, 80% capacity, and end of life were disassembled, and their electrodes were analyzed with X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Differential Scanning Calorimetry (DSC), and Brunauer-Emmett-Teller Isotherms (BET). These techniques analyzed different aspects of the electrodes’ physical and chemical properties, including Li plating, micro-cracking, SEI layer formation, and phase changes in cathode materials. BET and DSC measurements also provided insight into changes in the degree to which aged electrodes undergo thermal runaway events.Correlation of the postmortem materials analysis with the in situ electrochemical analysis gave an in-depth understanding of the origins of performance fade during cycling. The scale of this electrochemical and materials evaluation fills in gaps in the literature about battery performance and degradation beyond 80% capacity.Sandia National Laboratories is a multimission laboratory managed and operated by National Technology & Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525.

A Simplified Single-Layer Pseudo-4D Electrochemical/Thermal Model for Large-Format Li-Ion Pouch Cells

Ever since the first commercial Li-ion battery launched in 1991, Li-ion batteries have been the best available energy storage systems for consumer electronics [1]. With recent advances in cell capacity, cycle time and battery management systems, they have become even more popular as an ideal candidate for grid-scale energy storage and electric vehicles [2].When a battery is being charged or discharged, there is inevitable heat generation due to electrochemical reactions, ohmic resistance and entropy changes [3]. If the amount of heat generated is not sufficiently dissipated from the battery, it could substantially increase the cell temperature which leads to severe cell degradation and even catastrophic thermal runaway. Furthermore, large temperature inhomogeneity is commonly observed in large-format pouch cells due to the non-uniform local current density and reaction rate. Therefore, in order to maintain stable and durable performance, it is vital to understand the irregular heat generation and temperature distribution associated with cell geometry and properties, and design appropriate cooling techniques accordingly.Battery modeling is a useful tool to investigate the electrochemical reactions and consequent heat generation during charging and discharging. An experimentally validated battery model has the ability to accurately predict the cell response under different test conditions, eliminating the need for repeated lengthy experiments. Among all the existing Li-ion battery models, the pseudo-2D (P2D) model, originally proposed by John Newman and his students [4-6], is the most widely accepted electrochemical model for Li-ion batteries. Based on this, a few battery thermal models have been established by coupling a P2D electrochemical model with a 3D heat transfer model [7-9]. The electric and concentration fields are solved in a 1D unit-cell and are extracted to calculate the heat generation rates in a 3D battery geometry. However, such a method would introduce large errors in large-format pouch cells as the assumption of uniform current density and reaction rate is not valid.Therefore, in this study, we would like to propose a pseudo-4D (P4D) battery model, which extends the original P2D model from 1D to 3D battery geometry. The charge balance, mass balance and reaction kinetics, as well as energy balance, are spatially resolved for the entire battery geometry, considering the inhomogeneity of battery state properties. Furthermore, a scaling analysis is carried out via non-dimensionalization of the model equations to demonstrate that a single-layer cell would be sufficient to simulate the overall electrical and thermal performance of the battery which actually contains multiple cell layers. The complexity of the model can thereby be reduced to make the model more time-efficient.

Identifying degradation patterns of lithium ion batteries from impedance spectroscopy using machine learning

Forecasting the state of health and remaining useful life of Li-ion batteries is an unsolved challenge that limits technologies such as consumer electronics and electric vehicles. Here, we build an accurate battery forecasting system by combining electrochemical impedance spectroscopy (EIS)—a real-time, non-invasive and information-rich measurement that is hitherto underused in battery diagnosis—with Gaussian process machine learning. Over 20,000 EIS spectra of commercial Li-ion batteries are collected at different states of health, states of charge and temperatures—the largest dataset to our knowledge of its kind. Our Gaussian process model takes the entire spectrum as input, without further feature engineering, and automatically determines which spectral features predict degradation. Our model accurately predicts the remaining useful life, even without complete knowledge of past operating conditions of the battery. Our results demonstrate the value of EIS signals in battery management systems.

In Operando Acoustic Detection of Lithium Metal Plating in Commercial LiCoO2/Graphite Pouch Cells

Summary The characterization and detection of lithium metal plating during standard operation of commercial Li-ion batteries has been a long-term challenge; the nature of lithium metal plating is unpredictable and highly dependent on operating temperature and charge rate. In operando detection of lithium plating is critical for ongoing and future developments of conventional Li-ion batteries, including fast charging capabilities, extreme temperature applications, and lithium metal secondary batteries. In this study, we describe the use of acoustic ultrasound to detect lithium metal plating on commercial graphite anodes within a standard form factor. Extending from previous work on ultrasound as a battery diagnostic tool, this proof-of-concept study delineates statistically significant linear relationships between ultrasonic time-of-flight and graphite staging, and acoustic time-of-flight and post mortem electrochemical measurements to characterize the extent of lithium metal plating.

Comparative study of the implementation of tin and titanium oxide nanoparticles as electrodes materials in Li-ion batteries

Transition metal oxides potentially present higher specific capacities than the current anodes based on carbon, providing an increasing energy density as compared to commercial Li-ion batteries. However, many parameters could influence the performance of the batteries, which depend on the processing of the electrode materials leading to different surface properties, sizes or crystalline phases. In this work a comparative study of tin and titanium oxide nanoparticles synthesized by different methods, undoped or Li doped, used as single components or in mixed ratio, or alternatively forming a composite with graphene oxide have been tested demonstrating an enhancement in capacity with Li doping and better cyclability for mixed phases and composite anodes.

Solvent- and Anion-Dependent Li+–O2– Coupling Strength and Implications on the Thermodynamics and Kinetics of Li–O2 Batteries

Lithium–oxygen (Li–O2) batteries offer considerably higher gravimetric energy density than commercial Li-ion batteries (up to three times) but suffer from poor power, cycle life, and round-trip eff...

Perspective on Commercial Li-ion Battery Testing, Best Practices for Simple and Effective Protocols

Validation is an integral part of any study dealing with modeling or development of new control algorithms for lithium ion batteries. Without proper validation, the impact of a study could be drastically reduced. In a perfect world, validation should involve testing in deployed systems, but it is often unpractical and costly. As a result, validation is more often conducted on single cells under control laboratory conditions. Laboratory testing is a complex task, and improper implementation could lead to fallacious results. Although common practice in open literature, the protocols used are usually too quickly detailed and important details are left out. This work intends to fully describe, explain, and exemplify a simple step-by-step single apparatus methodology for commercial battery testing in order to facilitate and standardize validation studies.

The measurement of electrochemical noise of a Li-ion battery during charge-discharge cycling

For the first time electrochemical noise of a commercial Li-ion battery was measured during discharge via a constant value resistor for 1500 cycles. Spectral and statistical analyses were carried out. Both the power spectral density frequency dependence level and noise amplitude were increasing during battery cycling. Distribution diagrams, skewness and kurtosis values demonstrated unchanged normal noise distribution during cycling. Linear dependencies of the current power spectral density values on cycle number were found in the low-frequency band. Dependencies of the power spectral density on the DC-current value were measured at different stages of charge–discharge cycling. The total progress of electrochemical noise growth during cycling was divided into three stages with different prevalent battery degradation types: film growth, active material exfoliation, and structural changes.

Influence of Charge Cutoff Voltage on the Cycling Behavior of LiNi0.5Mn0.3Co0.2O2 Cathode

Layered oxide, LiNi0.5Mn0.3Co0.2O2 (NMC532), is commonly used in the commercial high energy Li-ion batteries. However, such layered oxide cathode always faces the dilemma between high capacity and stable cycling. Upper charge cutoff voltage is one of the important factors that strongly influences both capacity and cycle life, unfortunately, exhibiting an opposite effect. A choice of an appropriate upper charge cutoff voltage is expected to achieve the balance between these two performance metrics. Therefore, it is of great significance to comprehensively understand the effect of incremental upper voltages, ranging from normally used cutoff voltage to slight overcharge voltage, on the cycling behaviors of the NMC532 cathode material. In this work, the systematic studies about the effect of the upper voltage on the NMC532 cathode material are investigated. Physical characterizations, i.e., ex situ synchrotron X-ray diffraction and X-ray absorption spectroscopy, provide information on the degradation of NMC532 material. Post-mortem analysis via combined scanning electron microscopy and electrochemical impedance spectroscopy reveals the degradation of the cathode-electrolyte-interface at high voltages. This comprehensive study shows the fundamental interplay among many electrochemically relevant factors, especially at different charge cutoff voltages.

Understanding Adverse Effects of Temperature Shifts on Li-Ion Batteries: An Operando Acoustic Study

Studies related to battery performance and long-term health of commercial Li-ion batteries (LIBs) typically have a fixed temperature parameter. However, commercial LIBs are subject to temperature fluctuations due to their local environment and operating conditions, and these transient temperatures are well known to impact long-term stability. Herein, we demonstrate the adverse effects of temperature shifts, and show that transitioning from low temperature to higher temperature can lead to catastrophic failure within practical temperature ranges experienced by commercial LIBs. We show there exists an Arrhenius relationship between the rate of acoustic attenuation and the magnitude of the temperature shift. A combination of acoustic attenuation, which marks gassing occurrence during cycling, and post mortem chemical analyses provides further mechanistic insight into the Li-rich solid electrolyte interphase (SEI) formation at low temperatures and subsequent reactions with the electrolyte at higher temperatures. Further, several strategies to prevent or mitigate catastrophic failure are introduced. On a broader scale, this research further highlights the importance of temperature and current controls integration into battery management systems (BMS) for both safety and extension of cycle life as battery systems move toward fast charge (>3 C) capability.

Improved Stability and Cyclability of Ceramic Solid Electrolyte by Coating Polymer

Rechargeable all-solid-state lithium (Li) metal batteries show improved safety and energy density compared to commercial Li-ion batteries using liquid electrolyte. As the key component of Li metal batteries, ceramic solid-state electrolyte has attracted great interest because of its high ion conductivity and great potential in interfacing with Li metal. Ceramic electrolyte has a more stable interface with Li metal than liquid electrolyte, but chemical reaction and Li dendrite growth at the electrolyte/Li interface are still significant, which causes device degradation and failure by cycling of Li plating and stripping. Unlike ceramic electrolyte, polymer electrolyte has a relatively stable interface with Li metal and better mechanical flexibility. Therefore, we introduced a polymer electrolyte coating to protect the ceramic electrolyte from direct contact with Li metal. The galvanotactic cycling Li plating/striping data on the devices with (without) the coating illustrates increased (decreased) overall conductivity and cyclability of the test cell by the cycling. Nanometer-scale ionic-transport imaging, based on atomic force microscopy, shows that cycling degrades the ceramic-only electrolyte by partially blocking ionic transport in areas; in contrast, cycling on the polymer-coated electrolyte improves ionic conductivity. Compared with the ceramic-only electrolyte, this novel polymer electrolyte coating on ceramic electrolyte shows less degradation when in contact with Li metal.