面向高性能锂-硫二次电池应用的非对称电极-电解质界面

锂-硫电池具有高的理论电芯比能量和低成本,是极具应用前景的下一代电化学储能技术,已被广泛研究。实用化锂-硫电池技术目前面临的挑战主要包括正极侧电活性硫物种在充放电过程中的不可逆损失,负极侧枝晶形核生长,以及因活性硫迁移至负极而导致的界面副反应,上述问题会导致电池工况条件下性能迅速衰退,引发电池失效和安全问题。本工作中,我们提出通过设计非对称的电极-电解质界面稳定锂-硫电池正负极电化学,协同促进电极/电解质体相和界面电荷输运,从而延长电池循环寿命,显著提升电化学性能。本文所讨论的策略有望指导电池界面理性设计,助力实现高性能的锂-硫电池。

Roadmap for rechargeable batteries:present and beyond

Rechargeable batteries currently hold the largest share of the electrochemical energy storage market,and they play a major role in the sustainable energy transition and industrial decarbonization to respond to global climate change.Due to the increased popularity of consumer electronics and electric vehicles,lithium-ion batteries have quickly become the most successful rechargeable batteries in the past three decades,yet growing demands in diversified application scenarios call for new types of rechargeable batteries.Tremendous efforts are made to developing the next-generation post-Li-ion rechargeable batteries,which include,but are not limited to solid-state batteries,lithium–sulfur batteries,sodium-/potassium-ion batteries,organic batteries,magnesium-/zinc-ion batteries,aqueous batteries and flow batteries.Despite the great achievements,challenges persist in precise understandings about the electrochemical reaction and charge transfer process,and optimal design of key materials and interfaces in a battery.This roadmap tends to provide an overview about the current research progress,key challenges and future prospects of various types of rechargeable batteries.New computational methods for materials development,and characterization techniques will also be discussed as they play an important role in battery research.

二次电池研究进展

能源的存储和利用是当今科学和技术发展中的重大课题之一,尤其是作为高效的电能/化学能转化装置的二次电池相关技术一直是科学家研究的热点领域。在此背景下,本文较为系统地介绍目前二次电池的重要研究进展,将从二次电池的发展历史引入,再到其相关的基础理论知识的介绍。随后较为详细地讨论当前不同体系的二次电池及相关应的关键材料的研究进展,涉及到锂离子电池、钠离子电池、钾离子电池、镁离子电池、锌离子电池、钙离子电池、铝离子电池、氟离子电池、氯离子电池、双离子电池、锂-硫(硒)电池、钠-硫(硒)电池、钾-硫(硒)电池、多价金属-硫基电池、锂-氧电池、钠-氧电池、钾-氧电池、多价金属-氧气电池、锂-溴(碘)电池、水系金属离子电池、光辅助电池、柔性电池、有机电池、金属-二氧化碳电池等。此外,也介绍了电池研究中常见的电极反应过程表征技术,包括冷冻电镜、透射电镜、同步辐射、原位谱学表征、磁性表征等。本文将有助于研究人员对二次电池进行全面系统的了解与把握,并为之后二次电池的研究提供很好的指导作用。

Co3O4 modified Ag/g-C3N4 composite as a bifunctional cathode for lithium-oxygen battery

Rechargeable lithium-oxygen(Li-O2)batteries have appeal to enormous attention because they demonstrate higher energy density than the state-of-the-art Li-ion batteries.Whereas,their practical application is impeded by several challenging problems,such as the low energy round trip efficiencies and the insufficient cycle life,due to the cathode passivation caused by the accumulation of discharge products.Developing efficient catalyst for oxygen reduction and evolution reactions is effective to reduce the overpotentials in Li-O2cells.In our work,we report a Co3O4modified Ag/g-C3N4nanocomposite as a bifunctional cathode catalyst for Li-O2cells.The g-C3N4substrate prevents the accumulation of Ag and Co3O4nanoparticles and the presence of Ag NPs improves the surface area of g-C3N4and electronic conductivity,significantly improving the oxygen reduction/evolution capabilities of Co3O4.Due to a synergetic effect,the Ag/g-C3N4/Co3O4nanocomposite demonstrates a higher catalytic activity than each individual constituent of Co3O4or Ag/g-C3N4for the ORR/OER on as catalysts in Li-O2cells.As a result,the Ag/gC3N4/Co3O4composite shows impressive electrochemical performance in a Li-O2battery,including high discharge capacity,small gap between charge and discharge potential,and high cycling stability.

Insights into the nitride-regulated processes at the electrolyte/electrode interface in quasi-solid-state lithium metal batteries

Gel polymer electrolytes(GPEs)are one of the promising candidates for high-energy-density quasi-solid-state lithium metal batteries(QSSLMBs),for their high ionic conductivity and excellent interfacial compatibility.The comprehension of dynamic evolution and structure-reactivity correlation at the GPE/Li interface becomes significant.Here,in situ electrochemical atomic force microscopy(EC-AFM)provides insights into the LiNO_(3)-regulated micromechanism of the Li plating/stripping processes upon cycles in GPE-based LMBs at nanoscale.The additive LiNO_(3)induces the formation of amorphous nitride SEI film and facilitates Li^(+) ion diffusion.It stabilizes a compatible interface and regulates the Li nucleation/growth at steady kinetics.The deposited Li is in the shape of chunks and tightly compact.The Li dissolution shows favorable reversibility,which guarantees the cycling performance of LMBs.In situ AFM monitoring provides a deep understanding into the dynamic evolution of Li deposition/dissolution and the interphasial properties of tunable SEI film,regulating the rational design of electrolyte and optimizing interfacial establishment for GPE-based QSSLMBs.

Stable Li storage in micron-sized SiO_(x) particles with rigid-flexible coating

Micrometre-sized electrode materials have distinct advantages for battery applications in terms of energy density,processability,safety and cost.For the silicon monoxide anode that undergoes electrochemical alloying reaction with Li,the Li(de)intercalation by micron-sized active particles usually accompanies with a large volume variation,which pulverizes the particle structure and leads to rapidly faded storage performance.In this work,we proposed to stabilize the electrochemistry vs.Li of the micron-SiO_(x) anode by forming a rigid-flexible bi-layer coati ng on the particle surface.The coati ng consists of pyrolysis carbon as the inner layer and polydopamine as the outer layer.While the inner layer guarantees high structural rigidity at particle surface and provides efficient pathway for electron conduction,the outer layer shows high flexibility for maintaining the integrity of micrometre-sized particles against drastic volume variation,and together they facilitate formation of stable solid electrolyte interface on the SiO_(x) particles.A composite an ode prepared by mixing the coated micron-SiOx with graphite delivered improved Li storage performance,and promised a high-capacity,long-life LiFePO_(4)/SiO_(x)-graphite pouch cell.Our strategy provides a general and feasible solution for building high-energy rechargeable batteries from micrometre-sized electrode materials with significant volume variation.

A flame-retardant binder with high polysulfide affinity for safe and stable lithium–sulfur batteries

Lithium-sulfur(Li-S) batteries have shown promises for the next-generation, high-energy electrochemical storage, yet are hindered by rapid performance decay due to the polysulfide shuttle in the cathode and safety concerns about potential thermal runaway. To address the above challenges, herein, we show a flame-retardant cathode binder that simultaneously improves the electrochemical stability and safety of batteries. The combination of soft and hard segments in the polymer framework of binders allows high flexibility and mechanical strength for adapting to the drastic volume change during the Li(de)intercalation of the S cathode. The binder contains a large number of polar groups, which show the high affinity to polysulfides so that they help to anchor active S species at the cathode. These polar groups also help to regulate and facilitate the Li-ion transport, promoting the kinetics of polysulfide conversion reaction. The binder contains abundant phosphine oxide groups, which, in the case of battery's thermal runaway, decompose and release PO· radicals to quench the combustion reactions and stop the fire. Consequently, Li-S batteries using the new cathode binder show the improved electrochemical performance, including a low-capacity decay of 0.046% per cycle for 800 cycles at 1 C and favorable rate capabilities of up to 3 C. This work offers new insights on the practical realization of high-energy rechargeable batteries with stable storage electrochemistry and high safety.

Hydrogen isotope effects: A new path to high-energy aqueous rechargeable Li/Na-ion batteries

Aqueous rechargeable Li/Na-ion batteries have shown promise for sustainable large-scale energy storage due to their safety,low cost,and environmental benignity.However,practical applications of aqueous batteries are plagued by water's intrinsically narrow electrochemical stability window,which results in low energy density.In this perspective article,we review several strategies to broaden the electrochemical window of aqueous electrolytes and realize high-energy aqueous batteries.Specifically,we highlight our recent findings on stabilizing aqueous Li storage electrochemistry using a deuterium dioxide-based aqueous electrolyte,which shows significant hydrogen isotope effects that trigger a wider electrochemical window and inhibit detrimental parasitic processes.

Strategies for improving the storage performance of silicon-based anodes in lithium-ion batteries

Silicon has attracted much attention as a promising anode material for lithium-ion batteries (LIBs) due to its high theoretical capacity and rich resource abundance. However, the practical battery use of Si is challenged by its low conductivity and drastic volume variation during the Li uptake/release process. Tremendous efforts have been made on shrinking the particle size of Si into nanoscale so that the volume variation could be accommodated. However, the bare nano-Si material would still pulverize upon (de)lithiation. Moreover, it shows an excessive surface area to invite unlimited growth of solid electrolyte interface that hinders the transportation of charge carriers, and an increased interparticle resistance. As a result, the Si nanoparticles gradually lose their electrical contact during the cycling process, which accounts for poor thermodynamic stability and sluggish kinetics of the anode reaction versus Li. To address these problems and improve the Li storage performance of nano-Si anode, proper structural design should be applied on the Si anode. In this perspective, we will briefly review some strategies for improving the electrochemistry versus Li of nano-Si materials and their derivatives, and show opinions on the optimal design of nanostructured Si anode for advanced LIBs.

Advances of polymer binders for silicon-based anodes in high energy density lithium-ion batteries

Conventional lithium-ion batteries(LIBs)with graphite anodes are approaching their theoretical limitations in energy density.Replacing the conventional graphite anodes with high-capacity Si-based anodes represents one of the most promising strategies to greatly boost the energy density of LIBs.However,the inherent huge volume expansion of Si-based materials after lithiation and the resulting series of intractable problems,such as unstable solid electrolyte interphase layer,cracking of electrode,and especially the rapid capacity degradation of cells,severely restrict the practical application of Sibased anodes.Over the past decade,numerous reports have demonstrated that polymer binders play a critical role in alleviating the volume expansion and maintaining the integrity and stable cycling of Si-based anodes.In this review,the state-of-the-art designing of polymer binders for Si-based anodes have been systematically summarized based on their structures,including the linear,branched,crosslinked,and conjugated conductive polymer binders.Especially,the comprehensive designing of multifunctional polymer binders,by a combination of multiple structures,interactions,crosslinking chemistries,ionic or electronic conductivities,soft and hard segments,and so forth,would be promising to promote the practical application of Si-based anodes.Finally,a perspective on the rational design of practical polymer binders for the large-scale application of Si-based anodes is presented.

Air-stability of sodium-based layered-oxide cathode materials

Sodium-ion batteries have the potential to be an alternative to lithium-ion batteries especially for applications such as large-scale grid energy storage. The development of suitable cathode materials is crucial to the commercialization of sodium-ion batteries.Sodium-based layered-type transition metal oxides are promising candidates as cathode materials as they offer decent energy density and are easy to be synthesized. Unfortunately, most layered oxides suffer from poor air-stability, which greatly increases the cost of manufacturing and handling. The air-sensitivity severely limits the development and commercial application of sodium-ion batteries. A review that summarizes the latest understanding and solutions of air-sensitivity is desired. In this review,the background and fundamentals of sodium-based layered-type cathode materials are presented, followed by a discussion on the latest research on air-sensitivity of these materials. The mechanism is complex and involves multiple chemical and physical reactions. Various strategies are shown to alleviate some of the corresponding problems and promote the feasible application of sodium-ion batteries, followed by an outlook on current and future research directions of air-stable cathode materials. It is believed that this review will provide insights for researchers to develop practically relevant materials for sodium-ion batteries.

Photocatalytic CO2 reduction highly enhanced by oxygen vacancies on Pt-nanoparticle-dispersed gallium oxide

Photocatalytic CO2 reduction on metal-oxide-based catalysts is promising for solving the energy and environmental crises faced by mankind. The oxygen vacancy （Vo） on metal oxides is expected to be a key factor affecting the efficiency of photocatalytic CO2 reduction on metal-oxide-based catalysts. Yet, to date, the question of how an Vo influences photocatalytic CO2 reduction is still unanswered. Herein, we report that, on Vo-rich gallium oxide coated with Pt nanoparticles （Vo-rich Pt/Ga203）, CO2 is photocatalytically reduced to CO, with a highly enhanced CO evolution rate （21.0umol.h-1） compared to those on Vo-poor Pt/Ga2O3 （3.9 gmol-h-1） and Pt/TiO2（P25） （6.7 gmol.h-1）. We demonstrate that the Vo leads to improved CO2 adsorption and separation of the photoinduced charges on Pt/Ga203, thus enhancing the photocatalytic activity of Pt/Ga203. Rational fabrication of an Vo is thereby an attractive strategy for developing efficient catalysts for photocatalytic CO2 reduction.

Boron-doped three-dimensional MXene host for durable lithium-metal anode

Lithium metal has been widely studied as one of the most promising anode materials for realizing the next-generation high-energy-density rechargeable batteries.However,its practical use in rechargeable batteries has been hindered by hazardous dendrite growth and huge volume variations during Li plating/stripping.Herein,we reported a borondoped three-dimensional(3D)layered MXene(Ti_(3)C_(2)T_(x))as the host of Li metal anode.The material was synthesized via a facile one-pot hydrothermal process.With uniform B-doping,the prepared 3D multilayered MXene sheets provided more sites for nucleation of Li metal,so that the deposited Li metal anode showed favorable cycling stability and a high Coulombic efficiency.With the use of the same host material,a hybrid lithium-metal battery with 3D Li anode coupling with LiFePO4 cathode showed long cycle life and favorable electrochemical stability.This work shed lights on reasonable structural and compositional design of host materials that enables high-performance Li-metal anode toward practical realization of highenergy rechargeable batteries。

Biotemplated synthesis of three-dimensional porous MnO/C-N nanocomposites from renewable rapeseed pollen： An anode material for lithium-ion batteries

Lithium-ion batteries （LIBs） are currently recognized as one of the most popular power sources available. To construct advanced LIBs exhibiting long-term endurance, great attention has been paid to enhancing their poor cycle stabilities. As the performance of LIBs is dependent on the electrode materials employed, the most promising approach to improve their life span is the design of novel electrode materials. We herein describe the rational design of a three-dimensional （3D） porous MnO/C-N nanoarchitecture as an anode material for long cycle life LIBs based on their preparation from inexpensive, renewable, and abundant rapeseed pollen （R-pollen） via a facile immersion-annealing route. Remarkably, the as-prepared MnO/C-N with its optimized 3D nanostructure exhibited a high specific capacity （756.5 mAh·g^-1 at a rate of 100 mA·g^-1）, long life span （specific discharge capacity of 513.0 mAh·g^-1, -95.16% of the initial reversible capacity, after 400 cycles at 300 mA·g^-1）, and good rate capability. This material therefore represents a promising alternative candidate for the high-performance anode of next-generation LIBs.

Na_(3)Zr_(2)Si_(2)PO_(12) solid-state electrolyte with glass-like morphology for enhanced dendrite suppression

Rechargeable batteries based on solid-state electrolytes are of great interest and importance for the next-generation energy storage due to their high energy output and improved safety.For building the solid-state batteries,Na_(3)Zr_(2)Si_(2)PO_(12)(NZSP)represents a promising candidate as it features high chemical stability against air exposure and a high Na^(+)conductivity.NZSP pellets were usually calcined at a high temperature,and the high volatility of Na and P elements easily led to the formation of impurity phase.In this work,the effects of calcination temperature and stoichiometry on the phase purity and ionic conductivity of the NZSP electrolyte were studied.At an elevated sintering temperature,the NZSP electrolyte showed a high ionic conductivity owing to decreased porosity,and the highest ionic conductivity at 30℃was observed to be 2.75×10^(-5)S·cm^(-1)with an activation energy of 0.41 eV.For the stoichiometry,the introduction of 5 mol%excessive P results in formation of more Na_(3)PO_(4) and glass-like phase at the grain boundary,which caused the blurred grain boundary and reduced grain barrier,and effectively suppressed Na dendrite growth,then accounted for improved cycling performance of a Na‖Na symmetric cell.Our work provided insights on reasonable design and preparation of NZSP electrolyte towards practical realization of solid-state Na-metal batteries.

Chalcogen cathode and its conversion electrochemistry in rechargeable Li/Na batteries

Chalcogen elements,such as sulfur(S),selenium(Se),tellurium(Te)and the interchalcogen compounds,have been studied extensively as cathode materials for the next-generation rechargeable lithium/sodium(Li/Na)batteries.The high energy output of the Li/Na-chalcogen battery originates from the two-electron conversion reaction between chalcogen cathode and alkali metal anode,through which both electrodes are able to deliver high theoretical capacities.The reaction also leads to parasitic reactions that deteriorate the chemical environment in the battery,and different cathode-anode combinations show their own features.In this article,we intend to discuss the fundamental conversion electrochemistry between chalcogen elements and alkali metals and its potential influence,either positive or negative,on the performance of batteries.The strategies to improve the conversion electrochemistry of chalcogen cathode are also reviewed to offer insights into the reasonable design of rechargeable Li/Nachalcogen batteries.

Prussian-blue materials:Revealing new opportunities for rechargeable batteries

The demand to increase energy density of rechargeable batteries for portable electronic devices and electric vehicles and to reduce the cost for grid-scale energy storage necessitates the exploration of new chemistries of electrode materials for rechargeable batteries.The open framework-structure of Prussian-blue materials has recently been demonstrated as a promising cathode host for a variety of monovalent and multivalent cations with the tunable working voltage and discharge capacities.Recent progress toward the application of Prussian-blue cathode materials for rechargeable batteries is reviewed,with special emphasis on charge-storage mechanisms of different insertion species,factors influencing electrochemical performances,and possible approaches to overcome their intrinsic limitations.