Dual Modification Strategy for Enhanced Cycling and Rate Performance of Ni-Rich Cathode Materials in Lithium-Ion Batteries.

A great challenge in the commercialization process of layered Ni-rich cathode material LiNixCoyMn1-x-yO2 (NCM, x ≥ 80%) for lithium-ion batteries is the surface instability, which is exacerbated by the increase in nickel content. The high surface alkalinity and unavoidable cathode/electrolyte interface side reactions result in significant decrease for the capacity of NCM material. Surface coating and doping are common and effective ways to improve the electrochemical performance of Ni-rich cathode material. In this study, an in situ reaction is induced on the surface of secondary particles of NCM material to construct a stable lithium sulfate coating, while achieving sulfur doping in the near surface region. The synergistic modification of lithium sulfate coating and lattice sulfur doping significantly reduced the content of harmful residual lithium compounds (RLCs) on the surface of NCM material, suppressed the side reactions between the cathode material surface and electrolyte and the degradation of surface structure of the NCM material, effectively improved the rate capability and cycling stability of the NCM material.

Rational Design of Ion-Conductive Layer on Si Anode Enables Superior-Stable Lithium-Ion Batteries.

Silicon (Si) is considered a promising commercial material for the next-generation of high-energy density lithium-ion battery (LIB) due to its high theoretical capacity. However, the severe volume changes and the poor conductivity hinder the practical application of Si anode. Herein, a novel core-shell heterostructure, Si as the core and V3 O4 @C as the shell (Si@V3 O4 @C), is proposed by a facile solvothermal reaction. Theoretical simulations have shown that the in-situ-formed V3 O4 layer facilitates the rapid Li+ diffusion and lowers the energy barrier of Li transport from the carbon shell to the inner core. The 3D network structure constructed by amorphous carbon can effectively improve electronic conductivity and structural stability. Benefiting from the rationally designed structure, the optimized Si@V3 O4 @C electrode exhibits an excellent cycling stability of 1061.1 mAh g-1 at 0.5 A g-1 over 700 cycles (capacity retention of 70.0%) with an average Coulombic efficiency of 99.3%. In addition, the Si@V3 O4 @C||LiFePO4 full cell shows a superior capacity retention of 78.7% after 130 cycles at 0.5 C. This study opens a novel way for designing high-performance silicon anode for advanced LIBs.

Unlocking the Power of Magnesium Batteries: Synergistic Effect of InSb-C Composites to Achieve Superior Electrochemical Performance.

Pure magnesium anode used in rechargeable magnesium batteries (RMB) exhibits high theoretical capacity but has been challenged by the passivation issue with conventional electrolytes. Alloy-type anodes have the potential to surpass this issue and have attracted increasing attention. However, the kinetic performance and stabilities of conventional alloy anodes are still constrained. In this study, the InSb-10%C anode is synthesized by a two-step high-energy ball milling process. The InSb-10%C anode exhibits a remarkably high capacity of up to 448 mA h g-1, significantly improved cycle performance (234 mA h g-1 at 100 cycles) and rate performance (168 mA h g-1 at 500 mA g-1). The above-mentioned superior performance of the InSb-10%C anode for RMBs is attributed to the cellular graphitized amorphous carbon composite structure (CGA) which effectively refines the particle size and restricts the volume expansion. Additionally, the reduced surface electron density of InSb combined with the high conductivity resulting from graphitization enhances the Mg2+ diffusion performance. Notably, the InSb-10%C anode demonstrates good compatibility with conventional halogen-free salt ether-based electrolytes in the full battery configuration.

Investigations on Tunnel-Structure MnO2 for Utilization as a High-Voltage and Long-Life Cathode Material in Aqueous Ammonium-Ion and Hybrid-Ion Batteries.

Recently, nonmetal NH4 + ions have attracted extensive attention for use as charge carries in the field of energy storage due to their abundant resources, environmental friendliness, and low cost. However, the development of aqueous ammonium-ion batteries (AAIBs) is constrained by the absence of high-voltage and long-life materials. Herein, different tunnel-structure MnO2 materials (α-, ß-, and γ-MnO2) are utilized as cathodes for AAIBs and hybrid-ion batteries and compared, and α-MnO2 is demonstrated to exhibit the most remarkable electrochemical performance. The α-MnO2 cathode material delivers the highest discharge capacity of 219 mAh g-1 at a current density of 0.1 A g-1 and the best cyclability with a capacity retention of 95.4% after 10 000 cycles at 1.0 A g-1. Moreover, aqueous ammonium-ion and hybrid-ion (ammonium/sodium ions) full batteries are successfully constructed using α-MnO2 cathodes. This work provides a novel direction for the development of aqueous energy storage for practical applications.

Surface Engineering of Cathode Materials: Enhancing the High Performance of Lithium-Ion Batteries.

The development and application of lithium-ion batteries present a dual global prospect of opportunity and challenge. With conventional energy sources facing reserve shortages and environmental issues, lithium-ion batteries have emerged as a transformative technology over the past decade, owing to their superior properties. They are poised for exponential growth in the realms of electric vehicles and energy storage. The cathode, a vital component of lithium-ion batteries, undergoes chemical and electrochemical reactions at its surface that directly impact the battery's energy density, lifespan, power output, and safety. Despite the increasing energy density of lithium-ion batteries, their cathodes commonly encounter surface-side reactions with the electrolyte and exhibit low conductivity, which hinder their utility in high-power and energy-storage applications. Surface engineering has emerged as a compelling strategy to address these challenges. This paper meticulously examines the principles and progress of surface engineering for cathode materials, providing insights into its potential advancements and charting its development trajectory for practical implementation.

Sequencing-Dependent Impact of Carbon Coating on Microstructure Evolution and Electrochemical Performance of Pre-lithiated SiO Anodes: Enhanced Efficiency and Stability via Pre-Coating Strategy.

Silicon monoxide (SiO) has attracted considerable interest as anode material for lithium-ion batteries (LIBs). However, their poor initial Coulombic efficiency (ICE) and conductivity limit large-scale applications. Prelithiation and carbon-coating are common and effective strategies in industry for enhancing the electrochemical performance of SiO. However, the involved heat-treatment processes inevitably lead to coarsening of active silicon phases, posing a significant challenge in industrial applications. Herein, the differences in microstructures and electrochemical performances between prelithiated SiO with a pre-coated carbon layer (SiO@C@PLi) and SiO subjected to carbon-coating after prelithiation (SiO@PLi@C) are investigated. A preliminary carbon layer on the surface of SiO before prelithiation is found that can suppress active Si phase coarsening effectively and regulate the post-prelithiation phase content. The strategic optimization of the sequence where prelithiation and carbon-coating processes of SiO exert a critical influence on its regulation of microstructure and electrochemical performances. As a result, SiO@C@PLi exhibits a higher ICE of 88.0%, better cycling performance and lower electrode expansion than SiO@PLi@C. The pouch-type full-cell tests demonstrate that SiO@C@PLi/Graphite||NCM811 delivers a superior capacity retention of 91% after 500 cycles. This work provides invaluable insights into industrial productions of SiO anodes through optimizing the microstructure of SiO in prelithiation and carbon-coating processes.

Double-Salts Super Concentrated Carbonate Electrolyte Boosting Electrochemical Performance of Ni-Rich LiNi0.90Co0.05Mn0.05O2 Lithium Metal Batteries.

Current lithium-ion batteries cannot meet the requirement of higher energy density with further large-scale application of electrical vehicles. Lithium metal batteries combined with Ni-rich layered oxides cathode are expected as the one of promising solutions, while the poor electrode and electrolyte interface impedes the commercial development of lithium metal batteries. A new double-salts super concentrated (DSSC) carbonate electrolyte is proposed to improve the electrochemical performance of LiNi0.90Co0.05Mn0.05O2 (NCM9055)||Li metal battery which exhibits stable cycling performance with the capacity retention of 93.04% and reversible capacity of 173.8 mAh g-1 after 100 cycles at 1 C, while cells with conventional 1 m diluted electrolyte remains only 60.55% and capacity of 114.2 mAh g-1. The double salts synergistic effect in super concentrated electrolyte promotes the formation for more balanced stable cathode electrolyte interface (CEI) inorganic compounds of CFx, LiNOx, SOF2, Li2SO4, and less LiF by X-ray photoelectron spectroscopy (XPS) test, and the uniform 2-3 nm rock-salt phase protection layer on the cathode surface by transmission electron microscope (TEM) characterization, improving the cycling performance of the Ni-rich NCM9055 layered oxide cathode. The DSSC electrolyte also can relief the Li dendrite growth on Li metal anode, as well as exhibit better flame retardance, promoting the application of more safety Ni-rich NCM9055||Li metal batteries.

Tuning A-Site Cation Deficiency in Pr0.5La0.5BaCo2O5+ δ Perovskite to Realize Large-Scale Hydrogen Evolution at 2000 mA cm-2.

Industrial-level hydrogen production from the water electrolysis requires reducing the overpotential (η) as much as possible at high current density, which is closely related to intrinsic activity of the electrocatalysts. Herein, A-site cation deficiency engineering is proposed to screen high-performance catalysts, demonstrating effective Pr0.5- xLa0.5BaCo2O5+ δ (P0.5- xLBC) perovskites toward alkaline hydrogen evolution reaction (HER). Among all perovskite compositions, Pr0.4La0.5BaCo2O5+ δ (P0.4LBC) exhibits superior HER performance along with unique operating stability at large current densities (J = 500-2000 mA cm-2 geo). The overpotential of ≈636 mV is achieved in P0.4LBC at 2000 mA cm-2 geo, which outperforms commercial Pt/C benchmark (≈974 mV). Furthermore, the Tafel slope of P0.4LBC (34.1 mV dec-1) is close to that of Pt/C (35.6 mV dec-1), reflecting fast HER kinetics on the P0.4LBC catalyst. Combined with experimental and theoretical results, such catalytic activity may benefit from enhanced electrical conductivity, enlarged Co-O covalency, and decreased desorption energy of H* species. This results highlight effective A-site cation-deficient strategy for promoting electrochemical properties of perovskites, highlighting potential water electrolysis at ampere-level current density.

Constructing Multi-Electron Reactions by Doping Mn2+ to Increase Capacity and Stability in K3.2V2.8Mn0.2(PO4)4/C of Phosphate Cathodes for Potassium-Ion Batteries.

Vanadium-based phosphate cathode materials (e.g., K3V2(PO4)3) have attracted widespread concentration in cathode materials in potassium-ion batteries owing to their stable structure but suffer from low capacity and poor conductivity. In this work, an element doping strategy is applied to promote its electrochemical performance so that K3.2V2.8Mn0.2(PO4)4/C is prepared via a simple sol-gel method. The heterovalent Mn2+ is introduced to stimulated multiple electron reactions to improve conductivity and capacity, as well as interlayer spacing. Galvanostatic intermittent titration technique (GITT) and in situ X-ray diffraction results further confirm that Mn-doping in the original electrode can obtain superior electrode process kinetics and structural stability. The prepared K3.2V2.8Mn0.2(PO4)4/C exhibits a high-capacity retention of 80.8% after 1 500 cycles at 2 C and an impressive rate capability, with discharge capacities of 87.6 at 0.2 C and 45.4 mA h g-1 at 5 C, which is superior to the majority of reported vanadium-based phosphate cathode materials. When coupled K3.2V2.8Mn0.2(PO4)4/C cathode with commercial porous carbon (PC) anode as the full cell, a prominent energy density of 175 Wh kg-1 is achieved based on the total active mass. Overall, this study provides an effective strategy for meliorating the cycling stability and capacity of the polyanion cathodes for KIB.

A new In Situ Oxidized 2D Layered MnBi2Te4 Cathode for High-Performance Aqueous Zinc-Ion Battery.

Recently, aqueous zinc ion batteries (AZIBs) with the superior theoretical capacity, high safety, low prices, and environmental protection, have emerged as a contender for advanced energy storage. However, challenges related to cathode materials, such as dissolution, instability, and structural collapse, have hindered the progress of AZIBs. Here, a novel AZIB is constructed using an oxidized 2D layered MnBi2Te4 cathode for the first time. The oxidized MnBi2Te4 cathode with large interlayer spacing and low energy barrier for zinc ion diffusion at 240 °C, exhibited impressive characteristics, including a high reversibility capacity of 393.1 mAh g-1 (0.4 A g-1), outstanding rate performance, and long cycle stability. Moreover, the corresponding aqueous button cell also exhibits excellent electrochemical performance. To demonstrate the application in practice in the realm of flexible wearable electronics, a quasi-solid-state micro ZIB (MZIB) is constructed and shows excellent flexibility and high-temperature stability (the capacity does not significantly degrade when the temperature reaches 100 °C and the bending angle exceeds 150°). This research offers effective tactics for creating high-performance cathode materials for AZIBs.

Electrolytes for Aluminum-Ion Batteries: Progress and Outlook.

Aluminum-ion batteries (AIBs), as electrochemical energy storage technologies, are advantageous because of their high theoretical specific capacity, lightweightness, zero pollution, safety, inexpensiveness, and abundant resources, which make them recent research hot spots. However, their electrolyte issues significantly limit their commercialization. The electrolyte choices for AIBs are significantly limited, and most of the available choices do not facilitate the three-electron-transfer reaction of Al3+/Al. Thus, this review presents an overview of recent advances in electrolytes, as well as modification strategies for AIBs, to clarify the limitations of existing AIB electrolytes and offer guidance for improving their performances. Furthermore, the advantages as well as limitations and possible solutions for each electrolyte are discussed, after which the future of AIB electrolytes is envisioned.

Temperature-Dependent Electrochemical Performance of Ta-Substituted SrCoO3 Perovskite for Supercapacitors.

Developing new electrode materials with good temperature-dependent electrochemical performance has become a great issue for the deployment of hybrid supercapacitors with wide temperature tolerance. In this work, a series of Ta-substituted SrCo1-x Tax O3-δ (x=0.05, 0.10, 0.15, 0.20) perovskites have been studied as positive electrodes for hybrid supercapacitors in terms of their structures, elemental valence states and electrochemical performances. Incorporating Ta into SrCoO3-δ perovskite not only stabilizes the crystallite structure but also notably improves electrochemical activities. The SrCo0.95 Ta0.05 O3-δ @CC delivers the highest specific capacity (Qsp ) of 227.91 C g-1 at 1 A g-1 , which is attributed to the highest oxygen vacancy content and the fastest oxygen diffusion kinetics. The hybrid supercapacitor SrCo0.95 Ta0.05 O3-δ @CC//AC@CC exhibits a high energy density of 22.82 Wh kg-1 @775.09 W kg-1 and a stable long-term cycle life (5000 cycles) with 90.7 % capacity retention. As temperature increases from 25 to 85 °C, the capacitance properties are improved at elevated temperatures for both electrode and device due to the increased electrolyte conductivity. The outstanding electrochemical results present that SrCo1-x Tax O3-δ perovskite holds good prospects for hybrid supercapacitors with wide temperature tolerance.

Porous Carbon Foam with Carbon Nanotubes as Cathode for Li-CO2 Batteries.

With the extensive use of fossil fuels, the ever-increasing greenhouse gas of mainly carbon dioxide emissions will result in global climate change. It is of utmost importance to reduce carbon dioxide emissions and its utilization. Li-CO2 batteries can convert carbon dioxide into electrochemical energy. However, developing efficient catalysts for the decomposition of Li2 CO3 as the discharge product represents a challenge in Li-CO2 batteries. Herein, we demonstrate a carbon foam composite with growing carbon nanotube by using cobalt as the catalyst, showing the ability to enhance the decomposition rate of Li2 CO3 , and thus improve the electrochemical performance of Li-CO2 batteries. Benefiting from its abundant pore structure and catalytic sites, the as-assembled Li-CO2 battery exhibits a desirable overpotential of 1.67 V after 50 cycles. Moreover, the overpotentials are 1.05 and 2.38 V at current densities of 0.02 and 0.20 mA cm-2 , respectively. These results provide a new avenue for the development of efficient catalysts for Li-CO2 batteries.

The Utilization of Metal-Organic Frameworks and Their Derivatives Composite in Supercapacitor Electrodes.

Up to now, the mainstream adoption of renewable energy has brought about substantial transformations in the electricity and energy sector. This shift has garnered considerable attention within the scientific community. Supercapacitors, known for their exceptional performance metrics like good charge/discharge capability, strong power density, as well as extended cycle longevity, have gained widespread traction across various sectors, including transportation and aviation. Metal-organic frameworks (MOFs) with unique traits including adaptable structure, highly customizable synthetic methods, and high specific surface area, have emerged as strong candidates for electrode materials. For enhancing the performance, MOFs are commonly compounded with other conducting materials to increase capacitance. This paper provides a detailed analysis of various common preparation strategies and characteristics of MOFs. It summarizes the recent application of MOFs and their derivatives as supercapacitor electrodes alongside other carbon materials, metal compounds, and conductive polymers. Additionally, the challenges encountered by MOFs in the realm of supercapacitor applications are thoroughly discussed. Compared to previous reviews, the content of this paper is more comprehensive, offering readers a deeper understanding of the diverse applications of MOFs. Furthermore, it provides valuable suggestions and guidance for future progress and development in the field of MOFs.

Selective Lattice Doping Enables a Low-Cost, High-Capacity and Long-Lasting Potassium Layered Oxide Cathode for Potassium and Sodium Storage.

Layered transition metal oxides are highly promising host materials for K ions, owing to their high theoretical capacities and appropriate operational potentials. To address the intrinsic issues of KxMnO2 cathodes and optimize their electrochemical properties, a novel P3-type oxide doped with carefully chosen cost-effective, electrochemically active and multi-functional elements is proposed, namely K0.57Cu0.1Fe0.1Mn0.8O2. Compared to the pristine K0.56MnO2, its reversible specific is increased from 104 to 135 mAh g-1. In addition, the Cu and Fe co-doping triples the capacity under high current densities, and contributes to long-term stability over 500 cycles with a capacity retention of 68 %. Such endeavor holds the potential to make potassium-ion batteries particularly competitive for application in sustainable, low-cost, and large-scale energy storage devices. In addition, the cathode is also extended for sodium storage. Facilitated by the interlayer K ions that protect the layered structure from collapsing and expand the diffusion pathway for sodium ions, the cathode shows a high reversible capacity of 144 mAh g-1, fast kinetics and a long lifespan over 1000 cycles. The findings offer a novel pathway for the development of high-performance and cost-effective sodium-ion batteries.

An Effective Strategy on Synthesizing a Stable SiOx-Based Anode for High Density Lithium-Ion Batteries.

Silicon oxides (SiOx) have received extensive attention as an promising anode candidate for next-generation lithium-ion batteries (LIBs). However, their commerical applications have been seriously hindered by low conductivity, large volume expansion and unstable soild-electrolyte interface (SEI) layer, which result in low intial coulombic efficiency, poor rate performance and short cycling lifepan. In this work, we demonstrate a simple way to prepare a series of SiOx materials with lithium fluoride (LiF) modified by hydrothermal method and carbothermal modification. When the mass ratio of SiOx and LiF equals 1:0.15, the long-term cycling capacity retention can be greatly improve form 30.2% to 76.7% after 200 cycles. The result is primarily because the enhancement of electrons and Li+-ions transport and the stability of SEI layer due to LiF addition. However, excess LiF addition can hinder the diffusion of Li+-ions. This study presents the great potential of LiF modified on SiOx anode materials for LIBs.

Research Advances of Cathode Materials for Rechargeable Aluminum Batteries.

Rechargeable aluminum ion batteries (AIBs) have recently gained widespread research concern as energy storage technologies because of their advantages of being safe, economical, environmentally friendly, sustainable, and displaying high performance. Nevertheless, the intense Coulombic interactions between the Al3+ ions with high charge density and the lattice of the electrode body lead to poor cathode kinetics and limited cycle life in AIBs. This paper reviews the recent advances in the cathode design of AIBs to gain a comprehensive understanding of the opportunities and challenges presented by current AIBs. In addition, the advantages, limitations, and possible solutions of each cathode material are discussed. Finally, the future development prospect of the cathode materials is presented.

Progress and Challenges of Vanadium Oxide Cathodes for Rechargeable Magnesium Batteries.

Among the challenges related to rechargeable magnesium batteries (RMBs) still not resolved are positive electrode materials with sufficient charge storage and rate capability as well as stability and raw material resources. Out of the materials proposed and studied so far, vanadium oxides stand out for these requirements, but significant further improvements are expected and required. They will be based on new materials and an improved understanding of their mode of operation. This report provides a critical review focused on this material, which is embedded in a brief overview on the general subject. It starts with the main strategic ways to design layered vanadium oxides cathodes for RMBs. Taking these examples in more detail, the typical issues and challenges often missed in broader overviews and reviews are discussed. In particular, issues related to the electrochemistry of intercalation processes in layered vanadium oxides; advantageous strategies for the development of vanadium oxide composite cathodes; their mechanism in aqueous, "wet", and dry non-aqueous aprotic systems; and the possibility of co-intercalation processes involving protons and magnesium ions are considered. The perspectives for future development of vanadium oxide-based cathode materials are finally discussed and summarized.

Ca-Doping Cobalt-Free Double Perovskite Oxide as a Cathode Material for Intermediate-Temperature Solid Oxide Fuel Cell.

Mixed oxygen ion and electron-conducting materials are viable cathodes for solid oxide fuel cells due to their excellent oxygen transport kinetics and mixed electrical conductivity, which ensure highly efficient operation at low and medium temperatures. However, iron-based double perovskite oxides usually exhibit poor electrocatalytic activity due to low electron and oxygen ion conductivity. In this paper, Ca is doped in PrBaFe2O5+δ A-site to improve the electrochemical performance of PrBaFe2O5+δ. Results show that replacing Pr with Ca does not change the crystal structure, and the Ca doping effectively increases the adsorbed oxygen content and accelerates the migration and diffusion rate of O2- to the electrolyte|cathode interface. The polarization resistance of the symmetric cell PC0.15BF|CGO|PC0.15BF is 0.033 Ω·cm2 at 800 °C, which is about 56% lower than that of PBF, confirming the enhancement of the mixed conduction of oxygen ions and electrons. In addition, the anode-supported single cell has a peak power density of 512 mW·cm-2 at 800 °C.

Reduced Graphene Oxide-Supported SrV4O9 Microflowers with Enhanced Electrochemical Performance for Sodium-Ion Batteries.

Sodium-ion batteries (SIBs) have received considerable attention in recent years. Anode material is one of the key factors that determine SIBs' electrochemical performance. Current commercial hard carbon anode shows poor rate performance, which greatly limits applications of SIBs. In this study, a novel vanadium-based material, SrV4O9, was proposed as an anode for SIBs, and its Na+ storage properties were studied for the first time. To enhance the electrical conductivity of SrV4O9 material, a microflower structure was designed and reduced graphene oxide (rGO) was introduced as a host to support SrV4O9 microflowers. The microflower structure effectively reduced electron diffusion distance, thus enhancing the electrical conductivity of the SrV4O9 material. The rGO showed excellent flexibility and electrical conductivity, which effectively improved the cycling life and rate performance of the SrV4O9 composite material. As a result, the SrV4O9@rGO composite showed excellent electrochemical performance (a stable capacity of 273.4 mAh g-1 after 200 cycles at 0.2 A g-1 and a high capacity of 120.4 mAh g-1 at 10.0 A g-1), indicating that SrV4O9@rGO composite can be an ideal anode material for SIBs.