Design towards recyclable micron-sized NaS cathode with self-refinement mechanism.

Sodium sulfide (NaS) as an initial cathode material in room-temperature sodium-sulfur batteries is conducive to get rid of the dependence on Na-metal anode. However, the micron-sized NaS that accords with the practical requirements is obstructed due to poor kinetics and severe shuttle effect. Herein, a subtle strategy is proposed via regulating NaS redeposition behaviours.

Promoting Cathodic Kinetics and Anodic Stability in Practical Room-Temperature Sodium-Sulfur Batteries with Bifunctional Electrolytes.

The development of room-temperature (RT) sodium-sulfur (Na-S) batteries is severely hindered due to the slow kinetics of the S cathode and the instability of the Na-metal anode. To overcome this, we introduced a dual-functional electrolyte cosolvent, trifluoromethanesulfonamide (TFMSA). Short-chain NaS (1 ≤ ≤ 2) can be effectively dissolved due to the strong H-S bond interaction between TFMSA and sulfides, which changes the S conversion process, thereby effectively enhancing the conversion kinetics of the cathode.

K-O electrochemistry at the Au/DMSO interface probed by spectroscopy and theoretical calculations.

The reaction mechanism underpinning the operation of K-O batteries, particularly the O reactions at the positive electrode, is still not completely understood. In this work, by combining Raman spectroelectrochemistry and density functional theory calculations, we report on a fundamental study of K-O electrochemistry at a model interface of Au electrode/DMSO electrolyte. The key products and intermediates (O, KO and KO) are identified and their dependency on the electrode potential is revealed.

Interphasial Pre-lithiation and Reinforcement of Micro-Si Anode through Fluorine-free Electrolytes.

Micro-sized silicon (mSi) anodes offer advantages in cost and tap density over nanosized counterparts. However, its practical application still suffers from poor cyclability and low initial and later-cycle coulombic efficiency (CE), caused by the unstable solid electrolyte interphase (SEI) and irreversible lithiation of the surface oxide layer. Herein, a bifunctional fluorine (F)-free electrolyte was designed for the mSi anode to stabilize the interphase and improve the CE.

Co-Intercalation-Free Ether-Based Weakly Solvating Electrolytes Enable Fast-Charging and Wide-Temperature Lithium-Ion Batteries.

Ether-based electrolytes are competitive choices to meet the growing requirements for fast-charging and low-temperature lithium-ion batteries (LIBs) due to the low viscosity and low melting point of ether solvents. Unfortunately, the graphite (Gr) electrode is incompatible with commonly used ether solvents due to their irreversible co-intercalation into Gr interlayers. Here, we propose cyclopentyl methyl ether (CPME) as a co-intercalation-free ether solvent, which contains a cyclopentane group with large steric hindrance to obtain weakly solvating power with Li and a wide liquid-phase temperature range (-140 to +106 °C).

Interphase Engineering Enhanced Electro-chemical Stability of Prelithiated Anode.

Prelithiation is an essential technology to compensate for the initial lithium loss of lithium-ion batteries due to the formation of solid electrolyte interphase (SEI) and irreversible structure change. However, the prelithiated materials/electrodes become more reactive with air and electrolyte resulting in unwanted side reactions and contaminations, which makes it difficult for the practical application of prelithiation technology. To address this problem, herein, interphase engineering through a simple solution treatment after chemical prelithiation is proposed to protect the prelithiated electrode.

Temperature-dependent interphase formation and Li transport in lithium metal batteries.

High-performance Li-ion/metal batteries working at a low temperature (i.e., <-20 °C) are desired but hindered by the sluggish kinetics associated with Li transport and charge transfer.

Stress-Dispersed Superstructure of Sn (PO ) @PC Derived from Programmable Assembly of Metal-Organic Framework as Long-Life Potassium/Sodium-Ion Batteries Anodes.

The structures of anode materials significantly affect their properties in rechargeable batteries. Material nanosizing and electrode integrity are both beneficial for performance enhancement of batteries, but it is challenging to guarantee optimized nanosizing particles and high structural integrity simultaneously. Herein, a programmable assembly strategy of metal-organic frameworks (MOFs) is used to construct a Sn-based MOF superstructure precursor.

Multifunctional solvent molecule design enables high-voltage Li-ion batteries.

Elevating the charging cut-off voltage is one of the efficient approaches to boost the energy density of Li-ion batteries (LIBs). However, this method is limited by the occurrence of severe parasitic reactions at the electrolyte/electrode interfaces. Herein, to address this issue, we design a non-flammable fluorinated sulfonate electrolyte by multifunctional solvent molecule design, which enables the formation of an inorganic-rich cathode electrolyte interphase (CEI) on high-voltage cathodes and a hybrid organic/inorganic solid electrolyte interphase (SEI) on the graphite anode.

In Situ Detecting Thermal Stability of Solid Electrolyte Interphase (SEI).

Solid electrolyte interphase (SEI) plays an important role in regulating the interfacial ion transfer and safety of Lithium-ion batteries (LIBs). It is unstable and readily decomposed releasing much heat and gases and thus triggering thermal runaway. Herein, in situ heating X-ray photoelectron spectroscopy is applied to uncover the inherent thermal decomposition process of the SEI.

Tailoring polymer electrolyte ionic conductivity for production of low- temperature operating quasi-all-solid-state lithium metal batteries.

The stable operation of lithium-based batteries at low temperatures is critical for applications in cold climates. However, low-temperature operations are plagued by insufficient dynamics in the bulk of the electrolyte and at electrode|electrolyte interfaces. Here, we report a quasi-solid-state polymer electrolyte with an ionic conductivity of 2.

Chemically Induced Activity Recovery of Isolated Lithium in Anode-free Lithium Metal Batteries.

The anode-free lithium metal battery is considered to be an excellent candidate for the new generation energy storage system because of its higher energy density and safety than the traditional lithium metal battery. However, the continuous generation of SEI or isolated Li hinders its practical application. In general, the isolated Li is considered electrochemically inactive because it loses electrical connection with the current collector.

50C Fast-Charge Li-Ion Batteries using a Graphite Anode.

Li-ion batteries have made inroads into the electric vehicle market with high energy densities, yet they still suffer from slow kinetics limited by the graphite anode. Here, electrolytes enabling extreme fast charging (XFC) of a microsized graphite anode without Li plating are designed. Comprehensive characterization and simulations on the diffusion of Li in the bulk electrolyte, charge-transfer process, and the solid electrolyte interphase (SEI) demonstrate that high ionic conductivity, low desolvation energy of Li , and protective SEI are essential for XFC.

Platinum atomic clusters embedded in polyoxometalates-carbon black as an efficient and durable catalyst for hydrogen evolution reaction.

Platinum-based catalysts are regarded as the Holy Grail of hydrogen evolution reaction (HER). As a benchmark catalyst for HER, the commercial Pt/C catalyst has low Pt utilization efficiency and high cost, which hinders its commercialization. Atomic clusters-based catalysts show high efficiency of atom utilization and high performance toward electrocatalysis.

Deciphering the Role of Fluoroethylene Carbonate towards Highly Reversible Sodium Metal Anodes.

Sodium metal anodes (SMAs) suffer from extremely low reversibility (<20%) in carbonate-based electrolytes-this piece of knowledge gained from previous studies has ruled out the application of carbonate solvents for sodium metal batteries. Here, we overturn this conclusion by incorporating fluoroethylene carbonate (FEC) as cosolvent that renders a Na plating/stripping efficiency of >95% with conventional NaPF salt at a regular concentration (1.0 M).

Interfacial Barrier of Ion Transport in Poly(ethylene oxide)-LiLaZrO Composite Electrolytes Illustrated by Li-Tracer Nuclear Magnetic Resonance Spectroscopy.

Fundamental understanding of the lithium-ion transport mechanism in polymer-inorganic composite electrolyte is crucially important for the rational design of composite electrolytes for solid-state batteries. In this work, the Li ion transport pathway in a model composite electrolyte of PEO containing sparsely dispersed LLZO (PEO-LLZO) was studied by an advanced characterization technique, i.e.

Direct Spectroscopic Evidence for Solution-Mediated Oxygen Reduction Reaction Intermediates in Aprotic Lithium-Oxygen Batteries.

A fundamental understanding of the reaction process is essential to predict and enhance the performance of electrochemical devices. As a central reaction in aprotic lithium-oxygen (Li-O) batteries, the oxygen reduction reaction (ORR) has been confronted with the "sudden-death" phenomenon caused by the cathode passivation from discharge product LiO. The soluble catalyst (e.

Cryo-EM for battery materials and interfaces: Workflow, achievements, and perspectives.

The emerging cryogenic electron microscopy (cryo-EM) has demonstrated its power and essential role in probing the beam-sensitive battery materials and delivering new insights. With the increasing interest in cryo-EM for battery materials and interfaces, herein we provide the strategies of obtaining fresh and native structural information with minimal artifacts, including sample preparation, transferring, imaging, and data interpretation. We summarize the recent achievements enabled by cryo-EM and point out some unsolved/potential questions in terms of the bulk materials, solid-solid interface, and solid-liquid interfaces of batteries.

Anionic Effect on Enhancing the Stability of a Solid Electrolyte Interphase Film for Lithium Deposition on Graphite.

Graphitic carbons and their lithium composites have been utilized as lithium deposition substrates to address issues such as the huge volume variation and dendritic growth of lithium. However, new problems have appeared, including the severe exfoliation of the graphite particles and the instability of the solid electrolyte interphase (SEI) film when metallic lithium is plated on the graphite. Herein, we enhance the stability of the SEI film on the graphite substrate for lithium deposition in an electrolyte of lithium bis(fluorosulfonyl)imide (LiFSI) dissolved in the carbonate solvent, thereby improving the lithium plating/stripping cycle on it.

Reversible Cycling of Graphite Electrodes in Propylene Carbonate Electrolytes Enabled by Ethyl Isothiocyanate.

As one of the greatest inventions in the history of electrochemistry, the lithium-ion battery (LIB) has radically transformed human beings' daily life by powering portable electronics and electric vehicles. When we look back upon the long and arduous effort devoted to the development of the LIB technology, it is found that the birth of LIBs could have been even earlier if reversible cycling of the graphite electrode had been realized in the propylene carbonate (PC) electrolyte, one of the few dominating electrolytes extensively used in nonaqueous electrochemistry long before the concept of LIBs. In this work, a functional electrolyte additive, that is, ethyl isothiocyanate, has been identified to enable the reversible Li ion intercalation/de-intercalation into/out of the graphite electrode in PC electrolyte by forming a high-quality solid electrolyte interphase (SEI) on the graphite electrode.