高比能锂离子电池层状富锂正极材料改性策略研究进展

层状富锂材料具有超过250 mAh·g-1的高可逆比容量,被认为是下一代高比能锂离子电池最具商业化前景的正极材料之一。然而,层状富锂材料在实际应用之前仍需解决诸多挑战,如高电压氧释放、层状到岩盐相的结构变化、过渡金属离子迁移等结构劣化,并由此带来了较低的初始库伦效率、电压/容量的衰减以及循环寿命的不足。针对以上问题,进行层状富锂材料改性无疑是一种行之有效的方法。本综述全面介绍了层状富锂材料的结构、组分以及电化学性能,在此基础上对材料改性策略进行了系统阐述,详细介绍了体相掺杂、表面包覆、缺陷设计、离子交换和微结构调控等一系列改性策略的现状以及发展趋势,最终提出了高容量和长循环层状富锂材料和高比能锂离子电池的设计思路。

Status and challenges facing representative anode materials for rechargeable lithium batteries

Rechargeable lithium batteries have been widely regarded as a revolutionary technology to store renewable energy sources and extensively researched in the recent several decades.As an indispensable part of lithium batteries,the evolution of anode materials has significantly promoted the development of lithium batteries.However,since conventional lithium batteries with graphite anodes cannot meet the ever-increasing demands in different application scenarios(such as electric vehicles and large-scale power supplies)which require high energy/power density and long cycle life,various improvement strategies and alternative anode materials have been exploited for better electrochemical performance.In this review,we detailedly introduced the characteristics and challenges of four representative anode materials for rechargeable lithium batteries,including graphite,Li_(4)Ti_(5)O_(12),silicon,and lithium metal.And some of the latest advances are summarized,which mainly contain the modification strategies of anode materials and partially involve the optimization of electrode/electrolyte interface.Finally,we make the conclusive comments and perspectives,and draw a development timeline on the four anode materials.This review aims to offer a good primer for newcomers in the lithium battery field and benefit the structure and material design of anodes for advanced rechargeable lithium batteries in the future.

In-situ/operando characterization techniques in lithium-ion batteries and beyond

Nowadays,in-situ/operando characterization becomes one of the most powerful as well as available means to monitor intricate reactions and investigate energy-storage mechanisms within advanced batteries.The new applications and novel devices constructed in recent years are necessary to be reviewed for inspiring subsequent studies.Hence,we summarize the progress of in-situ/operando techniques employed in rechargeable batteries.The members of this large family are divided into three sections for introduction,including bulk material,electrolyte/electrode interface and gas evolution.In each part,various energy-storage systems are mentioned and the related experimental details as well as data analysis are discussed.The simultaneous strategies of various in-situ methods are highlighted as well.Finally,current challenges and potential solutions are concluded towards the rising influence and enlarged appliance of in-situ/operando techniques in the battery research.

In situ X-ray diffraction and thermal analysis of LiNi0.8Co0.15Al0.05O2 synthesized via co-precipitation method

LiNi0.9Co0.15Al0.05O2 （NCA） material is successfully synthesized with a modified co-precipitation method,in which NH3,H2O and EDTA are used as two chelating agents. The obtained LiNi0.9Co0.15Al0.05O2 materialhas well-defined layered structure and uniform element distribution, which reveals an enhanced electro-chemical performance with a capacity retention of 97.9% after 100 cycles at 0.2 C, and reduced thermalrunaway from the isothermal calorimetry test. In situ X-ray diffraction （XRD） was employed to capturethe structural changes during the charge-discharge process. The reversible evolutions of lattice parame-ters （a, b, c, and V） further verify the structural stability.

Research Progress for the Development of Li-Air Batteries: Addressing Parasitic Reactions Arising from Air Composition

Li-air batteries are an extremely attractive technology for electrical energy storage,especially in long-range electric vehicles,owing to their high theoretical specific energy.However,many issues still exist before their practical realization.Herein,the sole complexity of electrode reaction in Li-air batteries is presented.And the critical components that influence the electrochemical performance of aprotic Li-air batteries operating in ambient air are discussed.These include the mechanisms and pathways of CO_(2)/Li_(2)CO_(3) and H_(2)O/LiOH,catalysts of CO_(2) reduction/evolution reactions,and reactions between the Li anode and air constituents.If these challenges can be solved,Li-air batteries will soon be realized for practical application.Some hot topics in field of Li-air batteries should be focused,such as the fundamental mechanism research referring to interfacial reactions of atmosphere components on porous electrode and Li metal anode,high-efficiency solid catalyst design,and discovery of suitable soluble redox mediators.

Hybrid polymer electrolyte for Li–O_2 batteries

Li–O_2 batteries have attracted much attention because of their high specific energy. However, safety problem generated mainly from the flammable organic liquid electrolytes have hindered the commercial use of Li–O_2 batteries. One of the competitive alternatives is polymer electrolytes due to their flexibility and non-flammable property. Moreover, the hybrid polymer electrolyte with enhanced electrochemical properties would be achieved by incorporating inorganic filler, liquid plasticizer and redox mediator into the polymer. While most researches of the hybrid polymer electrolyte focused on Li-ion batteries, few of them took account into its application in Li–O_2 batteries. In this review, we mainly discuss hybrid polymer electrolytes for Li–O_2 batteries with different composition. The critical issues including conductivity and stability of electrolytes are also discussed in detail. Our review provides some insights of hybrid polymer electrolytes for Li–O_2 batteries and offers necessary guidelines for designing the suitable hybrid polymer electrolyte for Li–O_2 batteries as well.

Tuning Interface Bridging Between MoSe2 and Three‑Dimensional Carbon Framework by Incorporation of MoC Intermediate to Boost Lithium Storage Capability

Interface engineering has been widely explored to improve the electrochemical performances of composite electrodes,which governs the interface charge transfer,electron transportation,and structural stability.Herein,MoC is incorporated into MoSe2/C composite as an intermediate phase to alter the bridging between MoSe2-and nitrogen-doped three-dimensional(3D)carbon framework as MoSe2/MoC/N–C connection,which greatly improve the structural stability,electronic conductivity,and interfacial charge transfer.Moreover,the incorporation of MoC into the composites inhibits the overgrowth of MoSe2 nanosheets on the 3D carbon framework,producing much smaller MoSe2 nanodots.The obtained MoSe2 nanodots with fewer layers,rich edge sites,and heteroatom doping ensure the good kinetics to promote pseudo-capacitance contributions.Employing as anode material for lithium-ion batteries,it shows ultralong cycle life(with 90%capacity retention after 5000 cycles at 2 A g−1)and excellent rate capability.Moreover,the constructed LiFePO4//MoSe2/MoC/N–C full cell exhibits over 86%capacity retention at 2 A g−1 after 300 cycles.The results demonstrate the effectiveness of the interface engineering by incorporation of MoC as interface bridging intermediate to boost the lithium storage capability,which can be extended as a potential general strategy for the interface engineering of composite materials.

Electrolyte design principles for low-temperature lithium-ion batteries

Alongside the pursuit of high energy density and long service life,the urgent demand for low-temperature performance remains a long-standing challenge for a wide range of Li-ion battery applications,such as electric vehicles,portable electronics,large-scale grid systems,and special space/seabed/military purposes.Current Li-ion batteries suffer a major loss of capacity and power and fail to operate normally when the temperature decreases to-20℃.This deterioration is mainly attributed to poor Li-ion transport in a bulk carbonated ester electrolyte and its derived solid–electrolyte interphase(SEI).In this mini-review discussing the limiting factors in the Li-ion diffusion process,we propose three basic requirements when formulating electrolytes for low-temperature Liion batteries:low melting point,poor Liþaffinity,and a favorable SEI.Then,we briefly review emerging progress,including liquefied gas electrolytes,weakly solvating electrolytes,and localized high-concentration electrolytes.The proposed novel electrolytes effectively improve the reaction kinetics via accelerating Li-ion diffusion in the bulk electrolyte and interphase.The final part of the paper addresses future challenges and offers perspectives on electrolyte designs for low-temperature Li-ion batteries.

Solid-state Li-air batteries:Fundamentals,challenges,and strategies

The landmark Net Zero Emissions by 2050 Scenario requires the revolution of today's energy system for realizing nonenergy-related global economy.Advanced batteries with high energy density and safety are expected to realize the shift of end-use sectors toward renewable and clean sources of electricity.Present Li-ion technologies have dominated the modern energy market but face with looming challenges of limited theoretical specific capacity and high cost.Li-air(O2)battery,characterized by energy-rich redox chemistry of Li stripping/plating and oxygen conversion,emerges as a promising“beyond Li-ion”strategy.In view of the superior stability and inherent safety,a solid-state Li-air battery is regarded as a more practical choice compared to the liquid-state counterpart.However,there remain many challenges that retard the development of solid-state Li-air batteries.In this review,we provide an in-depth understanding of fundamental science from both thermodynamics and kinetics of solid-state Li-air batteries and give a comprehensive assessment of the main challenges.The discussion of effective strategies along with authoritative demonstrations for achieving highperformance solid-state Li-air batteries is presented,including the improvement of cathode kinetics and durability,solid electrolyte design,Li anode optimization and protection,as well as interfacial engineering.

Cation-mixing stabilized layered oxide cathodes for sodium-ion batteries

Sodium-ion batteries are promising for large-scale energy storage due to sodium's low cost and infinite abundance. The most popular cathodes for sodium-ion batteries, i.e., the layered sodium-containing oxides, usually exhibit reversible host rearrangement between P-type and O-type stacking upon charge/discharge. Herein we demonstrate that such host rearrangement is unfavorable and can be suppressed by introducing transition-metal ions into sodium layers. The electrode with stabilized P3-type stacking delivers superior rate capability, high energy efficiency, and excellent cycling performance. Owing to the cation-mixing nature, it performs the lowest lattice strain among all reported cathodes for sodium-ion batteries. Our findings highlight the significance of a stable host for sodium-ion storage and moreover underline the fundamental distinction in material design strategy between lithium-and sodium-ion batteries.

Halogen conversion-intercalation chemistry promises high energy density Li-ion battery

The state-of-art lithium-ion batteries(LIBs)have achieved great commercial success during the past decades.The intercalation mechanisms in graphite anode and lithium transition metal oxide enabled its long-term stability in organic electrolytes.The classic electrolyte formula of lithium hexafluorophosphate(Li PF6)in carbonate solvents provided a benign solid electrolyte interphase(SEI)on the electrode surface.Subsequent researches on materials and electrolytes have improved the electrochemical stability and energy density for LIBs.Nevertheless,their adoptions,especially in electric vehicles and power grid have been obstructed owing to the safety concerns and environmental impact.The flammable carbonate solvents are easy to trigger fire and cause cell failure.The common used LiPF6 is sensitive to moisture which increases much difficulty to eliminate trace water in practical application.

Oxygen vacancy promising highly reversible phase transition in layered cathodes for sodium-ion batteries

Phase transition is common during (de)-intercalating layered sodium oxides, which directly affects the structural stability and electrochemical performance. However, the artificial control of phase transition to achieve advanced sodium-ion batteries is lacking, since the remarkably little is known about the influencing factor relative to the sliding process of transition-metal slabs upon sodium release and uptake of layered oxides. Herein, we for the first time demonstrate the manipulation of oxygen vacancy concentrations in multinary metallic oxides has a significant impact on the reversibility of phase transition, thereby determining the sodium storage performance of cathode materials. Results show that abundant oxygen vacancies intrigue the return of the already slide transition-metal slabs between O_(3) and P_(3) phase transition, in contrast to the few oxygen vacancies and resulted irreversibility. Additionally, the abundant oxygen vacancies enhance the electronic and ionic conductivity of the Na0.9Ni0.3Co0.15Mn0.05Ti0.5O2 electrode, delivering the high initial Coulombic efficiency of 97.1%, large reversible capacity of 112.7 mAh·g−1, superior rate capability upon 100 C and splendid cycling performance over 1,000 cycles. Our findings open up new horizons for artificially manipulating the structural evolution and electrochemical process of layered cathodes, and pave a way in designing advanced sodium-ion batteries.

High-energy Mn-based layered cathodes for sodium-ion batteries

Sodium-ion batteries (SIBs) have great potential in large-scale energy storage applications due to the low cost and abundance of sodium resources (1,2)However, some critical issues, such as low energy density and inferior cycling performance, definitely hinder the practical application of SIBs, in part because of the bigger and heavier Na ion in contrast with the Li ion as an energy carrier (3)Recently, a surge of attention has been paid to the Mnbased materials due to the earth abundant and environmentally friendly manganese element [4,5].

Rechargeable battery operates at a record low temperature

Commercialized lithium ion batteries(LIBs)using intercalation compounds as electrode materials have found wide applications in kinds of portable devices and electric vehicles(EVs).

Correction to:Solid‑State Electrolytes for Lithium‑Ion Batteries:Fundamentals,Challenges and Perspectives

Correction to:Electrochem Energy Rev https://doi.org/10.1007/s41918-019-00048-0 In the version of this article initially published,the superscript number representing the affiliations of the first author Wenjia Zhao was incorrect and 1 was omitted.It should be 1 and 4.