Full Cell Performance Research Articles

Hybrid working mechanism enables highly reversible Zn electrodes

Zn dendrite growth and water-related side reactions have been criticized to hinder actual applications of aqueous Zn-ion batteries. To address these issues, a series of Zn interfacial modifications of building solid/electrolyte interphase (SEI) and nucleation layers have been widely proposed, however, their effectiveness remains debatable. Here, we report a boron nitride (BN)/Nafion layer on the Zn surface to efficiently solve Zn problems through combining the hybrid working mechanisms of SEI and nucleation layers. In our protective layer, Nafion exhibits the SEI mechanism by blocking water from the Zn surface and providing abundant channels for rapid Zn2+ transmission, whilst BN nanosheets induce Zn deposition underneath with a preferred (002) orientation. Accordingly, dendrite-free and side-reaction-free Zn electrode with (002) deposition under the protective layer is realized for the first time, as reflected by its high reversibility with average Coulombic efficiency of 99.2% for > 3000 ​h. The protected Zn electrode also shows excellent performance in full cells when coupling with polyaniline cathode under the strict condition of lean electrolyte addition. This work highlights insights for designing highly reversible metal electrodes towards practical applications.

A Stable Solid Polymer Electrolyte for Lithium Metal Battery with Electronically Conductive Fillers.

Electronic conduction in solid-polymer electrolytes is generally not desired, which causes leakage of electrons or energy loss, and the electronically conductive domains at electrode-electrolyte interfaces can lead to continuous decomposition of electrolytes and shorting issues. However, it is noticed in this work that in an insulating matrix, the conductive domains at certain aspects could also have positive effects on the electrolyte performance with proper control. This work evaluates the limitation and benefits of electronically conductive domains in a solid-polymer electrolyte system and discusses the approach to improve the electrolyte physicochemical properties with densified local electric field distribution, enhanced bulk dielectric property, and charge transfer. By deliberately introducing the conductive domains in a regular solid-polymer electrolyte, stable cycle life, low overpotential, and promising full cell performance could be achieved.

A Stable Solid Polymer Electrolyte for Lithium Metal Battery with Electronically Conductive Fillers

AbstractElectronic conduction in solid‐polymer electrolytes is generally not desired, which causes leakage of electrons or energy loss, and the electronically conductive domains at electrode‐electrolyte interfaces can lead to continuous decomposition of electrolytes and shorting issues. However, it is noticed in this work that in an insulating matrix, the conductive domains at certain aspects could also have positive effects on the electrolyte performance with proper control. This work evaluates the limitation and benefits of electronically conductive domains in a solid‐polymer electrolyte system and discusses the approach to improve the electrolyte physicochemical properties with densified local electric field distribution, enhanced bulk dielectric property, and charge transfer. By deliberately introducing the conductive domains in a regular solid‐polymer electrolyte, stable cycle life, low overpotential, and promising full cell performance could be achieved.

A Comparison of Carbonate-Based and Ether-Based Electrolyte Systems for Lithium Metal Batteries

Electrolytes play a critical role in enabling the stable cycling of rechargeable lithium (Li) metal batteries. While carbonate-based and ether-based electrolytes are widely investigated respectively with notably improved electrochemical performances in Li metal batteries, few works have been conducted for systematical understanding and comparison of these two systems. Here, we side-by-side investigated carbonate-based (dimethyl carbonate, DMC) and ether-based (1,2-dimethoxyethane, DME) electrolyte systems in terms of cathodic chemical/electrochemical stabilities, anodic stability, transport properties, Li morphology, Coulombic efficiency, and full cell performances. The experimental results indicate that ether-based electrolyte systems exhibit all-around superior compatibilities with Li metal anode, although the carbonate-based systems can be significantly improved from the commercial baseline by introducing fluorinated co-solvent. The ether-based systems, even at low concentrations, demonstrate acceptable anodic stability when charged to a reasonable cut-off voltage in practical applications. This work sheds light on advanced electrolyte development toward practical Li metal batteries.

A V-doped W3Nb14O44 anode in a Wadsley–Roth structure for ultra-fast lithium-ion half/full batteries

The V-doped W3Nb14O44 anode exhibits excellent electrochemical performance both in half and full cells due to an enhanced electronic conductivity and Li+ diffusion coefficient.

In-situ formation of LiF-rich solid-electrolyte interphases on 3D lithiophilic skeleton for stable lithium metal anode

Lithium (Li) metal with high theoretical capacity is considered as one of the important anode materials for the next-generation high-energy density batteries. However, the further commercial application of Li metal anode is hindered by the severe growth of uncontrollable Li dendrites and the destructive regrowth of unstable solid-electrolyte interphases (SEI) layer. Herein, through the combination of thin film deposition coating and in-situ fluoridation, a composite layer with the lithophilic layer and the LiF-rich SEI layer is realized on Cu foam current collector. Specifically, the lithiophilic layer on the surface of current collector helps to regulate the homogeneous Li plating/stripping behavior. More importantly, after in-situ fluoridation, the LiF-rich layer as a robustly artificial SEI can be in-situ generated on the surface of current collector during initial activation process to stabilize cycling performance with dendrite-free. Consequently, the well-designed 3D current collector enables dendrite-free Li deposition behavior, high average coulombic efficiency (97.74% for 500 cycles at 1 mA cm−2 & 1 mAh cm−2), stable Li plating/stripping behavior (over 2400 h with an ultra-low overpotential of 10 mV at 2 mA cm−2 & 2 mAh cm−2) and remarkable cycling stability/rate performance in both coin-type and pouch full cells. These encouraging results provide new insights into the design of high-performance Li metal anodes for the development of Li metal batteries.

Modulation and quantitative study of conformal electrode-electrolyte interfacial chemistry toward high-energy-density LiNi0.6Co0.2Mn0.2O2‖SiO-C pouch cells

High-nickel layered ternary cathode coupling with Si-based anode is one of the most promising strategies to realize high-energy-density batteries for power electric vehicles. However, undesired interfacial instability on both sides of cathode and anode causes continuous parasitic reactions and phase transformations, and results in fast degradation of the batteries. To address this issue, herein, in-situ reliable, compact and ionically conductive interface films are constructed effectively on both LiNi0.6Co0.2Mn0.2O2 (NMC622) cathode and SiO-C anode simultaneously by simply using a multifunctional additive, lithium difluorobis(oxalato) phosphate (LiDFBOP), due to its preferential redox reactivity then efficiently influencing the subsequent electrochemical behaviors of bulk electrolyte. These films shield the electrodes against the electrolyte attack, thus enabling long-term cycling stability and enhancing Coulombic efficiency of NMC622/SiO-C pouch cells. In addition, the highly Li-ionically conductive interphases also promote the electrode kinetics, which ensure the excellent rate capability as well as low temperature performance. The underlying interface formation mechanisms in term of specific consumption amount of additive on each electrode simultaneously are quantitatively studied by combining several complementary advanced characterizations techniques such as IC, TOF-SIMS, XPS and HRTEM etc., which not only benefit to predict the optimal addition content for cost-effective electrolyte in the actual conditions, but also validate that abundant Li-containing fluorinated inorganics and organic species regulate the microstructure and the composition of interface films, leading to enhanced ionic conductivity and intensified structure integrity, then finally contributing to the improved electrochemical performance of full pouch cells. New and in-depth insight in additive-involved interface reactions provides new opportunities for the design of rational surface films to realize high-energy batteries.

Design of Cuboidal FeNi2S4-rGO-MWCNTs Composite for Lithium-Ion Battery Anode Showing Excellent Half and Full Cell Performances

Ternary metal sulfides are projected as advanced lithium-ion battery (LIB) anodes due to their superior electronic conductivity and specific capacity compared to their respective oxide counterparts. Herein, a porous composite of cuboidal FeNi2S4 (FNS) with 2D reduced graphene oxide (rGO) and 1D multi-walled carbon nanotubes (MWCNTs) (composite name: FNS@GC) synthesised by an in-situ single-step hydrothermal process. The 1D/2D combined thin carbon coatings on the FeNi2S4 prevent aggregation during battery performance by increasing conductivity and resisting the volume changes at lithiation/de-lithiation processes. Consequently, the FNS@GC composite exhibits a commending electrochemical performance with a charge capacity of 797 mAh g−1 and a first cycle coulombic efficiency of ~67% with reversible capacity restoration property and excellent long-term cycling stability. Furthermore, FNS@GC//LiFePO4 full cell reveals its practical applicability as a LIB anode with a reversible capacity of 77 mAh g−1 at 50 mA g−1 current density.

Constructing a multi-functional polymer network for ultra-stable and safe Li-metal batteries

The practical application of lithium (Li) metal electrodes is impeded by Li dendrite growth and unstable solid electrolyte interphase (SEI). Herein, a multi-grafting polymer network, poly(dimethyl siloxane)-g-[poly(poly(ethylene glycol) methyl ether methacrylate)-r-sodium poly(p-styrene sulfonate)] (PPS), is chemically synthesized from reversible addition-fragmentation chain transfer (RAFT) polymerization. With integrated stretchability, ionic conductivity, and mechanical robustness, it serves a dual role to stabilize the Li electrode. As artificial SEI layer, the PPS enables superior electrochemical performance in half cells, symmetric cells, and full cells (PPS@Li/LiFePO4, capacity retention of >70% after 600 cycles). Utilized as solid polymer electrolyte (SPE), the all-solid-state Li/SPE/LiFePO4 full cell delivers excellent cycling performance with an unprecedented capacity retention of 90% over 1,700 cycles at 0.5 C and 81% over 1,000 cycles at 1.0 C. With high-voltage LiNi0.8Mn0.1Co0.1O2 (NMC811) as cathode, the Li/SPE/NMC811 cell exhibits an initial discharge capacity of 162.2 mAh g−1 with a capacity retention of 72% after 200 cycles. The assembled solid-state Li/SPE/LiFePO4 pouch cell with SPE exhibits stable cycling performance over 200 cycles with a capacity retention of 75% and still operates well even after curling, folding, and cutting, demonstrating great potential for achieving ultra-safe and high energy density batteries.

Densely Packed Li-Metal Growth on Anodeless Electrodes by Li+ -Flux Control in Space-Confined Narrow Gap of Stratified Carbon Pack for High-Performance Li-Metal Batteries.

Lithium (Li) is the "holy grail" for satisfying the increasing energy demand. This is because of its high theoretical capacity and low potential. Although Li is considered as a potential anode material, dendritic Li growth and the limited electrochemical properties continue to hinder its practical application. Structure-based self lithium ion (Li+ ) concentrating electrodes with high capacity and uniform Li+ -flux are recommended to overcome these shortcomings of Li. However, recent studies have been limited to structural perspectives. In addition, the electrokinetic principle of electrode materials remains a challenge. Herein, the space-confinement-based strategy is suggested for condensed Li+ -flux control in nanoscaled slit spaces that induce the dense Li growth on an anodeless electrode by using the stratified carbon pack (SCP). The micro/mesoporous slits of the SCP concentrate the electric field, which is strengthened by the space-confined electric field focusing, resulting in the accumulation of Li+ -flux in the host. The accumulated Li+ in host sites enables a uniform Li deposition with high capacity at high current density stably. Furthermore, SCPs have great compatibility with LiNi0.8 Co0.1 Mn0.1 O2 (NCM811) cathode, representing the outstanding full cell performance with Li deposited electrode which show the high specific of 115mAhg-1 at 4C during 350 cycles.

Lithium-ion battery full-cell performances of laboratory glass waste-derived SiO2@Fe2O3 nanocomposite anode

Lithium-ion battery full-cell performances of laboratory glass waste-derived SiO2@Fe2O3 nanocomposite anode

From Solid-Solution MXene to Cr-Substituted Na3V2(PO4)3: Breaking the Symmetry of Sodium Ions for High-Voltage and Ultrahigh-Rate Cathode Performance.

Stabilizing Na+ accessibility at high voltage and accelerating Na+ diffusivity are pressing issues to further enhance the energy density of the Na3V2(PO4)3 (NVP) cathode for sodium-ion batteries (SIBs). Herein, by taking a V/Cr solid-solution MXene as a precursor, a facile in-situ reactive transformation strategy to embed Cr-substituted NVP (NVCP) nanocrystals in a dual-carbon network is proposed. Particularly, the substituted Cr atom triggers the accessibility of additional Na+ in NVCP, which is demonstrated by an additional reversible redox plateau at 4.0 V even under extreme conditions. More importantly, the Cr atom alters the Na+ ordering at the Na2 sites with an additional intermediate phase formation during charging/discharging, thus reducing the energy barriers for Na+ migration. As a result, Na+ diffusivity in NVCP accelerates to 2-3 orders of magnitude higher than that of NVP. Eventually, the NVCP cathode exhibits extraordinarily high-rate capability (78 mA g-1 at 200 C and 68975 W kg-1), outstanding cycle stability (over 1500 cycles at 10 C), excellent low-temperature property, and full cell performance.

Sulfuretted Li- and Mn-rich cathode material with epitaxial spinel stabilizer for ultra-long cycle Li-ion battery

The utilization of Li- and Mn-rich layered cathode materials is an effective route to break the energy density bottleneck of lithium-ion batteries for practical applications. However, these materials always suffer from severe structural degradation and oxygen loss during long-term cycling process. Herein, the integrated modification was realized by epitaxial spinel phase film grown on the surface of Li1.2Mn0.54Ni0.13Co0.13O2 (LMR) and proper S elements doping to obtain outstanding electrochemical performance. The introduced spinel phase stabilizer can enhance Li ion conductivity and reduce the particle cracks and phase collapse during repeated cycling processes. The formation of TM-S bond configuration induced by S incorporation can effectively accelerate the lithium ions diffusion and suppress the undesired oxygen redox. Therefore, the LMRS@S cathode displays an excellent electrochemical performance: ultra-long-cycling stability with capacity retention of 82.1% after 600 cycles at 1 C, higher initial Coulomb efficiency (84.7% vs 76.3%) and excellent full cell performance (81.7% capacity retention after 140 cycles). The synergistic strategies with surface stabilizer and S-incorporation affords a promising way to design superior cycling performance LMR cathode material.

Benchmarking anion-exchange membranes for electrocatalytic carbon monoxide reduction

Performing carbon monoxide reduction in membrane electrode assembly configuration (MEA) is critical to achieving a high reaction rate while reducing cell resistance. Most studies examine the role of the cathode on product selectivity and cell stability, and comparatively little attention has been given to the membrane impact on cell performance. This study demonstrates that membrane properties such as water uptake, ion-exchange capacity, and functional groups alter the liquid product selectivity. Interestingly, we show that high ethanol crossover in conjunction with a suitable anode (NiFeO x ) tunes the acetate selectivity. Overall, membrane properties significantly affect cell stability and product selectivity in a membrane electrode assembly configuration. • Insights on product crossover through polymer membranes during CO electroreduction • The synergy between the membrane and anode tunes the selectivity of liquid products • Acetate Faradaic efficiency increased from 20% to 35% in a single pass conversion As a key component of carbon capture, utilization, and storage (CCUS), CO 2 utilization technologies are crucial for the circular carbon economy. Among all technologies being developed, CO2 electrolysis is particularly attractive because of its ability to convert CO 2 into various value-added products. Currently, research in CO 2 electrolysis primarily focuses on electrocatalyst development, whereas an ion-conductive polymer membrane did not receive sufficient attention despite the fact that it has a strong impact on full-cell performance. Here, we report the correlation between membrane properties and CO electroreduction performance. We present a new strategy to tune product selectivity by choosing a suitable membrane material and an electrochemically active anode. The understanding of membrane-electrode assembly performance presented in this study provides important insights for the future rational design of better membranes for CO 2 /CO electrolyzers. Suitable membrane properties and an active anode catalyst can tune the Faradaic efficiency of liquid products during CO electroreduction. Acetate Faradaic efficiency increased from 20% to 35% in single pass conversion using membranes with high ion-exchange capacity and active anode electrode for partial ethanol oxidation.

A facile one-step microwave synthesis of Pt deposited on N & P co-doped graphene intercalated carbon black - An efficient cathode electrocatalyst for PEM fuel cell

A facile, single step microwave assisted polyol route for simultaneously depositing platinum as well as co-doping graphene oxide, is herein proposed. However, low durability and full cell performance of Pt/NPG (platinum deposited on nitrogen phosphorous co-doped graphene) was observed due to restacking of graphene layers. This issue was addressed by intercalating CB into the graphene layers as spacers during the synthesis (in-situ addition of spacers - Pt/(NPG + S)). Moreover, to study the influence of spacers, external addition of spacers (ex-situ - Pt/(NPG) + S) were also examined. Results from our study indicate that in-situ addition of spacers- Pt/(NPG + S) enhanced the full cell performance (405 mW cm−2) and exhibited <40% ECSA loss (37.47%), thereby attaining DoE target. Thus, emerging as a durable cathode electrocatalyst (Pt/(NPG + S)) for PEM fuel cells.

Tuning Interface Mechanics Via β-Configuration Dominant Amyloid Aggregates for Lithium Metal Batteries.

Owing to abundant polar groups and good lithiophilicity, protein materials regain interest for application in lithium metal batteries (LMBs). Current proteins with an α-conformation for modifying lithium (Li) anodes possess typically poor mechanical properties, and there is therefore a significant need for advanced protein materials. Herein, a lysozyme-modified layer is coated onto the poly(vinylidene fluoride) electrospun mat for high mechanical strength and uniform Li-ion flux. The lysozyme membrane can regulate Li+ deposition behavior due to complete β-sheet configuration, high lithiophilicity sulfhydryl groups, and columnar nanopores. As a result, the lysozyme-modified Li metal anode exhibits a high stability performance of Li-Li symmetric cells (2800 h) and Li-LiFePO4 full cell (1450 cycles). Our strategy pushes the protein with β-sheet configuration toward the applications of next-generation LMBs.

Effects of Excessive Prelithiation on Full-Cell Performance of Li-Ion Batteries with a Hard-Carbon/Nanosized-Si Composite Anode

The effects of excessive prelithiation on the full-cell performance of Li-ion batteries (LIBs) with a hard-carbon/nanosized-Si (HC/N-Si) composite anode were investigated; HC and N-Si simply mixed at mass ratios of 9:1 and 8:2 were analyzed. CR2032-type half- and full-cells were assembled to evaluate the electrochemical LIB anode behavior. The galvanostatic measurements of half-cell configurations revealed that the composite anode with an 8:2 HC/N-Si mass ratio exhibited a high capacity (531 mAh g−1) at 0.1 C and superior current-rate dependence (rate performance) at 0.1–10 C. To evaluate the practical LIB anode performance, the optimally performing composite anode was used in the full cell. Prior to full-cell assembly, the composite anodes were prelithiated via electrochemical Li doping at different cutoff anodic specific capacities (200–600 mAh g−1). The composite anode was paired with a LiNi0.5Co0.2Mn0.3O2 cathode to construct full-cells, the performance of which was evaluated by conducting sequential rate and cycling performance tests. Prelithiation affected only the cycling performance, without affecting the rate performance. Excellent capacity retention was observed in the full-cells with prelithiation conducted at cutoff anodic specific capacities greater than or equal to 500 mAh g−1.

Engineering a hierarchical carbon supported magnetite nanoparticles composite from metal organic framework and graphene oxide for lithium-ion storage

Fe based metal organic framework (MOF) materials are being extensively investigated as a precursor sample for engineering carbon supported iron containing nanoparticles composites. Rational design and engineering Fe-containing MOFs with optimized structures using economic and eco-friendly methods is a challenging task. In this work, 1,3,5-benzenetricarboxylic acid (C9H6O6, trimesic acid, H3BTC) and metal Fe are employed to synthesize a MOF sample Fe-BTC in a mild hydrothermal condition. Moreover, with the addition of a small quantity of graphene oxide (GO) as dispersant, a redox coprecipitation reaction has taken place where small Fe-BTC domains well dispersed by reduced graphene oxide (RGO). The Fe-BTC/RGO intermediate sample is finally converted to the hierarchical Fe3O4@C/RGO composite, which delivers an ultrahigh specific capacity of 1262.61 mAh·g−1 at 200 mA·g−1 after 150 cycles and a superior reversible capacity of 910.65 mAh·g−1 at 1000 mA·g−1 after 300 cycles in half cells. The full cell performance for the Fe3O4@C/RGO composite have been studied. It is also revealed that the improved structural stability, high pseudocapacitive contribution and enhanced lithium-ion and electron transportation conditions jointly guarantee the outstanding lithium-ion storage performances for the Fe3O4@C/RGO composite over long-time cycling. The synthesized samples have good potential for wider application.

State-of-electrode (SOE) analytics of lithium-ion cells under overdischarge extremes

Overdischarge is an electrical abuse that may arise in a Li-ion battery module when a voltage imbalance occurs between series-connected cells. Although a wide range of studies has investigated overdischarge-induced aging at the full cell scale, the role of each electrode in degradation mechanisms and impacts of C-rates still require fundamental understanding. While most previous studies focus on copper dissolution, the inter-electrode crosstalk which occurs under an overdischarge scenario remains an open question. To fill these gaps, we deconvolute anode and cathode characteristics from the full cell performance during overdischarge abuses by fabricating Li-ion cells with a reference electrode configuration. Electrode potentials vs. Li/Li+ are measured and interpreted for increasingly severe overdischarge cycles under various C-rates. Deterioration of state of health is tracked by monitoring cell surface temperature, internal resistance, volumetric expansion, capacity retention, and impedance evolution. Surface microscopic characterizations are implemented to explore morphological changes and chemical state variations of electrodeposition with particle deformation. This study reveals the dual effect of the C-rate on explicit anode-centric failure mechanisms and implicit cathode-centric degradation pathways, providing new insights on overdischarge abuse fundamentals and effective mitigation strategies.

Seawater Battery: Strategies to Enable High Performance

Renewable energy sources such as solar, wind, and tide energy have been implemented to decrease air pollution due to common fossil fuel-generated electricity [1]. However, those systems are intermittent; creating the need for an energy storage system (ESS) that stores over-generated energy for later use and effectively matches the power fluctuation generated because of the sporadic demand throughout the day [2]. A possible solution to this problem is to couple renewable sources with rechargeable batteries. The most widespread electrochemical battery in the market is Lithium-ion, owing to its high energy density and lifetime and capability to resist frequent changes in charging-discharging rates [3]. Nevertheless, the current battery industry already requires 50% of the world's available lithium [4]. Foremost, lithium-ion battery is composed of critical metals such as cobalt, nickel, and manganese. The anticipated growing demand for these metals will lead to their scarcity [5]. Therefore, this study aims to develop strategy to enable a sodium-ion battery based on soluble seawater sodium and address the electrochemical and engineering problems.Seawater batteries have an open cathode compartment that can utilizes Na+ infinite source in the ocean as the active material [6]. There are three main components in this open structure seawater battery design. First is the non-aqueous liquid electrolyte facilitating the sodium ions transfer and deposition on the anode compartment [7-8]. Subsequently, the solid-state electrolyte (SSE) enables the flow of sodium ions from the sweater cathode to the anode which is typically copper current collector [9]. Lastly, a current collector that provides reaction sites for cathode reactions that could be made of carbon-based materials, such as carbon paper, carbon felt, or carbon cloth [10].The Solid-state electrolyte is the component that requires the most attention. It must have high ionic conductivity to increase sodium-ions transfers and maintain good mechanical and physical properties as it represents the interface between cathode and anode, preventing the water from penetrating the anode compartment and short-circuiting the cell.To increase its ionic conductivity, it is necessary to reduce its thickness as much as possible. Through the palletization and sintering process, a ceramic SSE was fabricated with a thickness of ~ 250 µm and ionic conductivity of 0.62 mS/cm. Subsequently, symmetric cells (Na||SSE||Cu) were assembled to further test the pellet's performance. Cells that were tested under continuous charge/discharge cycling for 360 cycles showed stable charge capacity and high Coulombic efficiency (> 95%). Performance of full cells using seawater at the cathode was also demonstrated. Addressing various issues such as water permeation through the SSE, electrode corrosion, Na deactivation in the anode, and catalytic activity of the carbon cathodes are also investigated. Figure 1. Charge/discharge profile of a symmetric Na||SSE||Cu cell at a current density of 0.10 mA/cm2.