Single-atom electrocatalysts for lithium-sulfur chemistry:Design principle,mechanism,and outlook

Lithium-sulfur batteries(LSBs)have been regarded as one of the promising candidates for the next-generation“lithium-ion battery beyond”owing to their high energy density and due to the low cost of sulfur.However,the main obstacles encountered in the commercial implementation of LSBs are the notorious shuttle effect,retarded sulfur redox kinetics,and uncontrolled dendrite growth.Accordingly,single-atom catalysts(SACs),which have ultrahigh catalytic efficiency,tunable coordination configuration,and light weight,have shown huge potential in the field of LSBs to date.This review summarizes the recent research progress of SACs applied as multifunctional components in LSBs.The design principles and typical synthetic strategies of SACs toward effective Li–S chemistry as well as the working mechanism promoting sulfur conversion reactions,inhibiting the lithium polysulfide shuttle effect,and regulating Li+nucleation are comprehensively illustrated.Potential future directions in terms of research on SACs for the realization of commercially viable LSBs are also outlined.

Recent progresses on designing and manufacturing of bulk refractory alloys with high performances based on controlling interfaces

Refractory alloys such as tungsten and molybdenum based alloys with high strength,thermal/electrical conductivity,low coefficient of thermal expansion and excellent creep resistances are highly desirable for applications in nuclear facilities,critical components in aerospace and defense components.However,the serious embrittlement limits the engineering usability of some refractory alloys.A lot of research results indicate that the performances of refractory alloys are closely related to the physical/chemical status,such as the interface dimension,interface type,interface composition of their grain boundaries(GBs),phase boundaries(PBs)and other interface features.This paper reviewed the recent progress of simulations and experiments on interface design strategies that achieve high performance refractory alloys.These strategies include GB interface purifying/strengthening,PB interface strengthening and PB/GB synergistic strengthening.Great details are provided on the design/fabrication strategy such as GB interface controlling,PB interface controlling and synergistic control of multi-scaled interfaces.The corresponding performances such as the mechanical property,thermal conductivity,thermal load resistance,thermal stability,irradiation resistance,and oxidation resistance are reviewed in the aspect to the effect of interfaces.In addition,the relationships between these interfaces and material properties are discussed.Finally,future developments and potential new research directions for refractory alloys are proposed.

Insight into Cellulose Nanosizing for Advanced Electrochemical Energy Storage and Conversion:A Review

Living in a world of heavy industrialization and confronted by the ever-deteriorating environment,the human race is now undertaking serious efforts to reach the target of carbon neutrality.One major step is to promote the development of sustainable electrochemical energy storage and conversion technologies based on green resources instead of the traditional nonreusable petroleum-based technologies.As an almost inexhaustible bioresource,nanocellulose derived from natural biomass exhibits outstanding physiochemical properties that could be well leveraged to bring about numerous opportunities for electrochemical processes.Through structure engineering,nanocellulose with a width of a few tens of nanometers and a length of up to micrometers could be realized.The drastic reduction in dimensions leads to superior mechanical,optical,and functional properties inaccessible to the bulky cellulose counterpart.In this review,different types of nanocellulose with distinctive physiochemical properties and their respective preparation methods are first examined.This is followed by a detailed and insightful analysis of the superiority and unprecedented performance gains that nanocellulose imparts to different electrochemical energy storage and conversion applications as a result of nanosizing.Finally,we humbly put forward our perspectives on the problems regarding current studies as well as on the future research direction for nanocellulose-mediated electrochemical processes to enable practical applications.This review is intended as guidance to initiate cross-disciplinary research effort in this engaging field and help evoke inspiration to effect solutions to critical energy issues of the day.