ZnO Additive Boosts Charging Speed and Cycling Stability of Electrolytic Zn–Mn Batteries

Electrolytic aqueous zinc-manganese(Zn–Mn) batteries have the advantage of high discharge voltage and high capacity due to two-electron reactions. However, the pitfall of electrolytic Zn–Mn batteries is the sluggish deposition reaction kinetics of manganese oxide during the charge process and short cycle life. We show that, incorporating ZnO electrolyte additive can form a neutral and highly viscous gel-like electrolyte and render a new form of electrolytic Zn–Mn batteries with significantly improved charging capabilities. Specifically, the ZnO gel-like electrolyte activates the zinc sulfate hydroxide hydrate assisted Mn^(2+) deposition reaction and induces phase and structure change of the deposited manganese oxide(Zn_(2)Mn_(3)O_8·H_(2)O nanorods array), resulting in a significant enhancement of the charge capability and discharge efficiency. The charge capacity increases to 2.5 mAh cm^(-2) after 1 h constant-voltage charging at 2.0 V vs. Zn/Zn^(2+), and the capacity can retain for up to 2000 cycles with negligible attenuation. This research lays the foundation for the advancement of electrolytic Zn–Mn batteries with enhanced charging capability.

From aqueous Zn-ion battery to Zn-MnO_(2) flow battery:A brief story

Aqueous Zn-ion battery(AZIB)has become an attractive technology because of its unique features of low cost,high safety and the eco-friendliness.MnO_(2) is the model cathode material for AZIB since the first report on reversible Zn-MnO_(2) battery,but recent studies have unveiled different charge storage mechanisms.Due to revamping of the electrochemistry and redesigning of the electrolyte and interface,there is tremendous performance enhancement in AZIB.This mini Review will first give a brief introduction of ZIB,including fundamentals of materials and components,and the progress in recent years.Then,a general classification of working mechanisms related to MnO_(2) in neutral and mildly acidic electrolyte is elaborated.Our focus is put on the recent blossoming Zn-MnO_(2) electrolytic mechanism,which has given birth to the Zn-MnO_(2) redox flow batteries that are highly promising for large-scale static energy storage.

Forming solid electrolyte interphase in situ in an ionic conducting Li_(1.5)Al_(0.5)Ge_(1.5)(PO_4)_3-polypropylene(PP) based separator for Li-ion batteries

A new concept of forming solid electrolyte interphases（SEI） in situ in an ionic conducting Li（1.5）Al（0.5）Ge（1.5）（PO4）3-polypropylene（LAGP-PP） based separator during charging and discharging is proposed and demonstrated. This unique structure shows a high ionic conductivity, low interface resistance with electrode, and can suppress the growth of lithium dendrite. The features of forming the SEI in situ are investigated by scanning electron microscopy（SEM） and x-ray photoelectron spectroscopy（XPS）. The results confirm that SEI films mainly consist of lithium fluoride and carbonates with various alkyl contents. The cell assembled by using the LAGP-coated separator demonstrates a good cycling performance even at high charging rates, and the lithium dendrites were not observed on the lithium metal electrode. Therefore, the SEI-LAGP-PP separator can be used as a promising flexible solid electrolyte for solid state lithium batteries.

Concentrated dual-salt electrolytes for improving the cycling stability of lithium metal anodes

Lithium（Li） metal is an ideal anode material for rechargeable Li batteries, due to its high theoretical specific capacity（3860 mAh/g）, low density（0.534 g/cm3）, and low negative electrochemical potential（-3.040 V vs. standard hydrogen electrode）. In this work, the concentrated electrolytes with dual salts, composed of Li[N（SO2F）2]（Li FSI） and Li[N（SO2CF3）2]（Li TFSI） were studied. In this dual-salt system, the capacity retention can even be maintained at 95.7%after 100 cycles in Li｜Li FePO4 cells. A Li｜Li cell can be cycled at 0.5 mA/cm2 for more than 600 h, and a Li｜Cu cell can be cycled at 0.5 m A/cm2 for more than 200 cycles with a high average Coulombi efficiency of 99%. These results show that the concentrated dual-salt electrolytes exhibit superior electrochemical performance and would be a promising candidate for application in rechargeable Li batteries.

Unraveling electrolyte solvation architectures for high-performance lithium-ion batteries

The design of advanced electrolytes hinges critically on a comprehensive comprehension of lithium-ion migration mechanisms within these electrochemical systems. Fluorination generally improves the stability and reduces the reactivity of organic compounds, making them potentially suitable for use in harsh conditions such as those found in a battery electrolyte. However,the specific properties, such as the solvation power, diffusivity, ion mobility, and so forth, would depend on the exact nature and extent of the fluorination. In this work, we introduce a theoretical framework designed to facilitate the autonomous creation of electrolyte molecular structures and craft methodologies to compute transport coefficients, providing a physical interpretation of fluoride systems. Taking fluorinated-1,2-diethoxyethanes as electrolyte solvents, we present and analyze the relationship between the electronic properties and atomic structures, and further correlate these properties to the transport coefficients, resulting in a good alignment with the experimental diffusion behaviors and Li-solvation structures. The insights derived from this research contribute to the methodological basis for high-throughput evaluation of prospective electrolyte systems, and consequently, propose strategic directions for the improvement of electrochemical cycle characteristics. This comprehensive exploration of the transport mechanisms enhances our understanding, offering avenues for further advancements in the field of lithium-ion battery technology.

The Transference Number

The performance of rechargeable batteries and other electrochemical systems depends on the rate at which the working ion(often a cation)is transported from one electrode to the other.The cation transference number is an important transport parameter that affects this rate.The purpose of this perspective is to distinguish between approximate and rigorous methods used in the literature to measure the transference number.We emphasize the fact that this parameter is dependent on the reference frame used in the analysis;care must be taken when comparing values obtained from different sources to account for differences in reference frames.We present data obtained from a well-characterized electrolyte.We compare rigorously determined transference numbers in two reference frames with values obtained by an approximate method.We conclude with a qualitative discussion of the relationship between the transference number and salt concentration gradients that are obtained when current is drawn through a battery。

Recent advances in energy storage mechanism of aqueous zinc-ion batteries

Aqueous rechargeable zinc-ion batteries(ZIBs)have recently attracted increasing research interest due to their unparalleled safety,fantastic cost competitiveness and promising capacity advantages compared with the commercial lithium ion batteries.However,the disputed energy storage mechanism has been a confusing issue restraining the development of ZIBs.Although a lot of efforts have been dedicated to the exploration in battery chemistry,a comprehensive review that focuses on summarizing the energy storage mechanisms of ZIBs is needed.Herein,the energy storage mechanisms of aqueous rechargeable ZIBs are systematically reviewed in detail and summarized as four types,which are traditional Zn^(2+)insertion chemistry,dual ions co-insertion,chemical conversion reaction and coordination reaction of Zn^(2+)with organic cathodes.Furthermore,the promising exploration directions and rational prospects are also proposed in this review.

Inhomogeneous lithium-storage reaction triggering the inefficiency of all-solid-state batteries

All-solid-state batteries offer an attractive option for developing safe lithium-ion batteries.Among the various solid-state electrolyte candidates for their applications,sulfide solid electrolytes are the most suitable owing to their high ionic conductivity and facile processability.However,their performance is extensively lower compared with those of conventional liquid electrolyte-based batteries mainly because of interfacial reactions between the solid electrolytes and high capacity cathodes.Moreover,the kinetic evolution reaction in the composite cathode of all-solid-state lithium batteries has not been actively discussed.Here,electrochemical analyses were performed to investigate the differences between the organic liquid electrolyte-based battery and all-solid-state battery systems.Combined with electrochemical analyses and synchrotron-based in situ and ex situ X-ray analyses,it was confirmed that inhomogeneous reactions were due to physical contact.Loosely contacted and/or isolated active material particles account for the inhomogeneously charged regions,which further intensify the inhomogeneous reactions during extended cycles,thereby increasing the polarization of the system.This study highlighted the benefits of electrochemo-mechanical integrity for securing a smooth conduction pathway and the development of a reliable homogeneous reaction system for the success of solid-state batteries.

High-temperature liquid Sn-air energy storage cell

A new type of a high temperature liquid metal-air energy storage cell based on solid oxide electrolyte has been successfully demonstrated at 750 ℃ by feeding metal Sn. In order to understanding the initial size effect of metal as a liquid fuel, we report here the impact of the thermal and electrochemical oxidation behavior of nano Sn （-100 nm）, comparing with micro-sized （-5 μm） and macro-sized （4350 μm） Sn. The thermogravimetric analysis and the monitoring OCV test indicate that the distinct property of nano-sized Sn results in a favorable thermal oxidation behavior near the melting point and a promising power performance due to enhanced fuel transport to the anode. However, the accumulated Sn oxide at the reaction interface during a discharge test towards the limitation of further electrochemical oxidation.

A novel tin-graphite dual-ion battery based on the sodium-ion electrolyte with high energy density

Subject Code:E02With the support by the National Natural Science Foundation of China and the Chinese Academy of Sciences,the research team led by Prof.Tang Yongbing(唐永炳)at the Functional Thin Films Research Center,Shenzhen Institutes of Advanced Technology,Chinese Academy of Sciences,developed a novel tin-graphite dual-ion battery based on sodium-ion electrolyte with high energy density,which

Organic materials-based cathode for zinc ion battery

The quest for advanced energy storage devices with cheaper,safer,more resource-abundant storage has triggered intense research into zinc ion batteries(ZIBs).Among them,organic materials as cathode materials for ZIBs have attracted great interest due to their flexible structure designability,high theoretical capacity,environmental friendliness,and sustainability.Although numerous organic electrode materials have been studied and different redox mechanisms have been proposed in the past decade,their electrochemical performance still needs further improvement,and the mechanisms require further exploration.This paper provides a systematical overview of three types of organic materials(bipolar-type conductive polymer,n-type conjugated carbonyl compounds,and p-type material)on the energy storage mechanisms and distinct characteristics.We then focus on discussing the design strategies to improve electrochemical performance.Furthermore,the challenges and future research directions are discussed to provide a foundation for further developing organic-based ZIBs.

A promising energy storage system:rechargeable Ni-Zn battery

The sharp depletion of fossil fuel resources and its associated increasingly deteriorated environmental pollution are vital challenging energy issues, which are one of the most crucial research hot spots in the twenty-first century.Rechargeable Ni–Zn batteries（RNZBs）, delivering high power density in aqueous electrolytes with stable cycle performance, are expected to be promising candidates to alleviate the current energy and environmental problems,and play an important role in green power sources. Many efforts have been focused on the investigations and improvements of RNZBs in recent decades, and it is necessary to summarize and review the achievements and challenges in this advancing field. In this paper, we review various batteries, compare and highlight the advantages of RNZBs, and introduce the recent advances in the development of electrode materials and electrolytes of RNZBs,especially the applications of novel nanostructured materials for the active electrodes. Some prospective investigation trends of RNZBs are also proposed and discussed.

Progress of electrode/electrolyte interfacial investigation of Li-ion batteries via in situ scanning probe microscopy

The electrode/electrolyte interface plays a cri- tical role in the performance of a Li-ion battery. In view of the dynamic and complex nature of the interface, in situ research approaches can provide valuable information of interfacial phenomena during battery operation. In situ scanning probe microscopy （SPM） is a powerful technique used for the interfacial investigation of the Li-ion batteries. The versatile SPM techniques and their various operation modes have been utilized to measure the morphology and other properties of the electrode interface at high resolu- tion. Herein, we discuss the related SPM techniques to study the topography, mechanics and electrochemistry re- search of electrodes. Recent progresses of in situ SPM research on the electrode/electrolyte interface are summa- rized. Finally, the outlook of the technique is discussed.

Ethylene sulfite based electrolyte for non-aqueous lithium oxygen batteries

Non-aqueous lithium-oxygen （Li-O2） batteries have been considered as the superior energy storage system due to their high-energy density, however, some challenges limit the practical application of Li- O2 batteries. One of them is the lack of stable electrolyte. In this communication, a novel electrolyte with ethylene sulfite （ES） used as solvent for Li-O2 batteries was reported. ES solvent showed low volatility and high electrochemical stability. Without a catalyst in the air-electrode of Li-O2 batteries, the batteries showed high specific capacity, good round-trip efficiency and cycling stability.

Estimating the thickness of diffusive solid electrolyte interface

electrolyte. The properties of lithium-ion (Li-ion) battery, such as cycle life, irreversible capacity loss, self-discharge rate, electrode corrosion and safety are usually ascribed to the quality of the SEI, which are highly dependent on the thickness. Thus, understanding the formation mechanism and the SEI thickness is of prime interest. First, we apply dimensional analysis to obtain an explicit relation between the thickness and the number density in this study. Then the SEI thickness in the initial charge-discharge cycle is analyzed and estimated for the first time using the Cahn-Hilliard phase-field model. In addition, the SEI thickness by molecular dynamics simulation validates the theoretical results. It has been shown that the established model and the simulation in this paper estimate the SEI thickness concisely within order-of-magnitude of nanometers. Our results may help in evaluating the performance of SEI and assist the future design of Li-ion battery.

Determination of anions in lithium-ion batteries electrolyte by ion chromatography

A sensitive and accurate method based on ion chromatography was established for determination of five lithium salts in lithium-ion batteries electrolytes. Chromatographic analyses were carried out on an anion exchange column at flow rate of 1 m L/min. Under the optimal conditions, five target anions（BF4^-,PF6^-, TFSI^-, BOB^-and FSI^-） exhibited satisfactory linearity with a correlation coefficient of 0.9996. The relative standard derivations of the target anions were less than less than 0.94%（n = 7）. The limits of detections were in the range of 0.068–0.29 mg/L with average spiked recoveries ranging from 96.8% to 105.1%.

Chloromethyl pivalate based electrolyte for non-aqueous lithium oxygen batteries

A novel electrolyte with chloromethyl pivalate （CP） used as solvent was first reported for non-aqueous lithium-oxygen （Li-O2） batteries. Since there are no α-H atoms in the structure of CP, the CP based electrolyte in both superoxide radical solution and real LifO2 battery environment showed good chemical stability against superoxide radicals, which was confirmed by ^1H NMR and ^13C NMR measurements. Without a catalyst in the cathode of Li-O2 batteries, the batteries showed high specific capacity and cycling stability.