In-situ constructed SnO_(2) gradient buffer layer as a tight and robust interphase toward Li metal anodes in LATP solid state batteries

Li_(1.3)Al_(0.3)Ti_(1.7)(PO_(4))_(3)(LATP),of much interest owing to its high ionic conductivity,superior air stability,and low cost,has been regarded as one of the most promising solid-state electrolytes for next-generation solid-state lithium batteries(SSLBs).Unfortunately,the commercialization of SSLBs is still impeded by severe interfacial issues,such as high interfacial impedance and poor chemical stability.Herein,we proposed a simple and convenient in-situ approach to constructing a tight and robust interface between the Li anode and LATP electrolyte via a SnO_(2)gradient buffer layer.It is firmly attached to the surface of LATP pellets due to the volume expansion of SnO_(2)when in-situ reacting with Li metal,and thus effectively alleviates the physical contact loosening during cycling,as confirmed by the mitigated impedance rising.Meanwhile,the as-formed SnO_(2)/Sn/LixSn gradient buffer layer with low electronic conductivity successfully protects the LATP electrolyte surface from erosion by the Li metal anode.Additionally,the LixSn alloy formed at the Li surface can effectively regulate uniform lithium deposition and suppress Li dendrite growth.Therefore,this work paves a new way to simultaneously address the chemical instability and poor physical contact of LATP with Li metal in developing low-cost and highly stable SSLBs.

Constructing BaTiO_(3)/TiO_(2)@polypyrrole composites with hollow multishelled structure for enhanced electromagnetic wave absorbing properties

BaTiO_(3)/TiO_(2)@polypyrrole(PPy)composites with hollow multishelled structure(HoMS)were constructed to enhance the electromagnetic wave absorbing properties of BaTiO_(3)-based absorbing material.BaTiO_(3)/TiO_(2)HoMSs were prepared by hydrothermal crystallization using TiO_(2)Ho MSs as template.Then,FeCl3 was introduced to initiate the oxidative polymerization of pyrrole monomer,forming BaTiO_(3)/TiO_(2)@PPy HoMSs successfully.The electromagnetic wave absorbing properties of BaTiO_(3)/TiO_(2)HoMSs and BaTiO_(3)/TiO_(2)@PPy Ho MSs with different shell number were investigated using a vector network analyzer.The results indicate that BaTiO_(3)/TiO_(2)@PPy HoMSs exhibit improved microwave absorption compared with BaTiO_(3)/TiO_(2)HoMSs.In particular,tripled-shelled BaTiO_(3)/TiO_(2)@PPy HoMS has the most excellent absorbing performance.The best reflection loss can reach up to-21.80 dB at 13.34 GHz with a corresponding absorber thickness of only 1.3 mm,and the qualified absorption bandwidth of tripled-shelled BaTiO_(3)/TiO_(2)@PPy HoMS is up to 4.2 GHz.This work paves a new way for the development of high-performance composite microwave absorbing materials.

A Comprehensive Study of a Low-Grade Heat-Driven Cooling and Power System Based on Heat Current Method

Combined cooling and power(CCP)system driven by low-grade heat is promising for improving energy efficiency.This work proposes a CCP system that integrates a regenerative organic Rankine cycle(RORC)and an absorption chiller on both driving and cooling fluid sides.The system is modeled by using the heat current method to fully consider nonlinear heat transfer and heat-work conversion constraints and resolve its behavior accurately.The off-design system simulation is performed next,showing that the fluid inlet temperatures and flow rates of cooling water as well as RORC working fluid strongly affect system performance.The off-design operation even becomes infeasible when parameters deviate from nominal values largely due to limited heat transfer capability of components,highlighting the importance of considering heat transfer constraints via heat current method.Design optimization aiming to minimize the total thermal conductance is also conducted.RORC efficiency increases by 7.9%and decreases by 12.4%after optimization,with the hot fluid inlet temperature increase from 373.15 to 403.15 K and mass flow rate ranges from 10 to 30 kg/s,emphasizing the necessity of balancing system cost and performance.

Decoding lithium batteries through advanced in situ characterization techniques

Given the energy demands of the electromobility market,the energy density and safety of lithium batteries(LBs)need to be improved,whereas its cost needs to be decreased.For the enhanced performance and decreased cost,more suitable electrode and electrolyte materials should be developed based on the improved understanding of the degradation mechanisms and structure–performance correlation in the LB system.Thus,various in situ characterization technologies have been developed during the past decades,providing abundant guidelines on the design of electrode and electrolyte materials.Here we first review the progress of in situ characterization of LBs and emphasize the feature of the multi-model coupling of different characterization techniques.Then,we systematically discuss how in situ characterization technologies reveal the electrochemical processes and fundamental mechanisms of different electrode systems based on representative electrode materials and electrolyte components.Finally,we discuss the current challenges,future opportunities,and possible directions to promote in situ characterization technologies for further improvement of the battery performance.

Novel Au nanoparticles-inlaid titanium paper for PEM water electrolysis with enhanced interfacial electrical conductivity

Proton-exchange membrane water electrolysis(PEM WE)is a particularly promising technology for renewable hydrogen produc-tion.However,the excessive passivation of the gas diffusion layer(GDL)will seriously affect the high surface-contact resistance and result in energy losses.Thus,a mechanism for improving the conductivity and interface stability of the GDL is an urgent issue.In this work,we have prepared a hydrophilic and corrosion resistant conductive composite protective coating.The polydopamine(PDA)film on the Ti surface,which was obtained via the solution oxidation method,ensured that neither micropores nor pinholes existed in the final hybrid coatings.In-situ reduced gold nanoparticles(AuNPs)improved the conductivity to achieve the desired interfacial contact resistance and further enhanced the corrosion resistance.The surface composition of the treated samples was investigated using scanning electron microscopy(SEM),transmis-sion electron microscopy(TEM),X-ray diffraction(XRD),and Fourier transform infrared spectroscopy(FTIR).The results indicated that the optimized reaction conditions included a pH value of 3 of HAuCl_(4) solution with PDA deposition(48 h)on papers and revealed the lowest con-tact resistance(0.5 mΩ·cm^(2))and corrosion resistance(0.001μA·cm^(−2))in a 0.5 M H_(2)SO_(4)+2 ppm F−solution(1.7 V vs.RHE)among all the modified specimens,where RHE represents reversible hydrogen electrode.These findings indicated that the Au-PDA coating is very appropriate for the modification of Ti GDLs in PEM WE systems.

Biomimetic three-dimensional multilevel nanoarray electrodes with superaerophobicity as efficient bifunctional catalysts for electrochemical water splitting

The design and preparation of cost-effective and durable catalysts for electrochemical water splitting are significant for the development and application of hydrogen production.Herein,inspired by the underwater superaerophobicity of fish scales,a three-dimensional multilevel nanoarray electrode with superaerophobicity was designed and fabricated by the hydrothermal method to solve the bubble shielding effect in electrochemical reactions.Benefiting from the high specific surface area,superaerophobic properties,Al doping,the Al-CoS_(2)nanosheets(NSs)/nickel foam(NF)-30 exhibits outstanding electrocatalytic activity and superior durability for electrochemical water splitting in 1 M KOH.Significantly,the Al-CoS_(2)NSs/NF-30 only required extremely low overpotential of 176 mV for oxygen evolution reaction(OER)to reach a current density of 10 mA·cm^(-2).Al-CoS_(2)NSs/NF-30 was employed as bifunctional electrode for electrochemical water splitting with a cell voltage of 1.58 V at 10 mA·cm^(-2).Meanwhile,Al-CoS_(2) NSs/NF-30 exhibited excellent durability(250 h@10 mA·cm^(-2)and 50 h@100 mA·cm^(-2)).The cobalt-based catalyst(Al-CoS_(2) NSs/NF-30)with superaerophobicity exhibits excellent performance in activity and durability,therefore is a promising electrochemical water splitting catalyst.