查看更多>>摘要：Manufacturing thin-film components is crucial for achieving high-efficiency and high-power thermal batteries(TBs).However,developing binders with low-gas production at the operating temperature range of TBs(400-550 ℃)has proven to be a significant challenge.Here,we report the use of acrylic acid derivative terpolymer(LA136D)as a low-volatile binder for thin-film cathode fabrication and studied the chain scission and chemical bond-breaking mechanisms in pyrolysis.It is shown LA136D defers to random-chain scission and cross-linking chain scission mechanisms,which gifts it with a low proportion of volatile products(Ψ,Ψ=39.2 wt％)at even up to 550 ℃,well below those of the conventional PVDF(77.6 wt％)and SBR(99.2 wt％)binders.Surprisingly,LA136D contributes to constructing a thermal shock-resistant cathode due to the step-by-step bond-breaking process.This is beneficial for the overall performance of TBs.In discharging test,the thin-film cathodes exhibited a remarkable 440％reduction in polarization and 300％enhancement in the utilization efficiency of cathode materials,while with just a slight increase of 0.05 MPa in gas pressure compared with traditional"thick-film"cathode.Our work highlights the potential of LA136D as a low-volatile binder for thin-film cathodes and shows the feasibility of manufacturing high-efficiency and high-power TBs through polymer molecule engineering.
查看更多>>摘要：SnO2,with its high theoretical capacity,abundant resources,and environmental friendliness,is widely regarded as a potential anode material for lithium-ion batteries(LIBs).Nevertheless,the coarsening of the Sn nanoparticles impedes the reconversion back to SnO2,resulting in low coulombic efficiency and rapid capacity decay.In this study,we fabricated a heterostructure by combining SnO2 nanoparticles with MoS2 nanosheets via plasma-assisted milling.The heterostructure consists of in-situ exfoliated MoS2 nanosheets predominantly in 1 T phase,which tightly encase the SnO2 nanoparticles through strong bonding.This configuration effectively mitigates the volume change and particle aggregation upon cycling.Moreover,the strong affinity of Mo,which is the lithiation product of MoS2,toward Sn plays a pivotal role in inhibiting the coarsening of Sn nanograins,thus enhancing the reversibility of Sn to SnO2 upon cycling.Consequently,the SnO2/MoS2 heterostructure exhibits superb performance as an anode material for LIBs,demonstrating high capacity,rapid rate capability,and extended lifespan.Specifically,discharged/charged at a rate of 0.2 A g-1 for 300 cycles,it achieves a remarkable reversible capacity of 1173.4 mAh g-1·Even cycled at high rates of 1.0 and 5.0 A g-1 for 800 cycles,it still retains high reversible capacities of 1005.3 and 768.8 mAh g-1,respectively.Moreover,the heterostructure exhibits outstanding electrochemical performance in both full LIBs and sodium-ion batteries.
查看更多>>摘要：The Fe-based anode of sodium-ion batteries attracts much attention due to the abundant source,low-cost,and high specific capacity.However,the low electron and ion transfer rate,poor structural stability,and shuttle effect of NaS2 intermediate restrain its further development.Herein,the Fe3O4/Fe/FeS tri-heterojunction node spawned N-carbon nanotube scaffold structure(FHNCS)was designed using the modified MIL-88B(Fe)as a template followed by catalytic growth and sulfidation process.During catalytic growth process,the reduced Fe monomers catalyze the growth of N-doped carbon nanotubes to connect the Fe3O4/Fe/FeS tri-heterojunction node,forming a 3D scaffold structure.Wherein the N-doped carbon promotes the transfer of electrons between Fe3O4/Fe/FeS particles,and the tri-heterojunction facilitates the diffusion of electrons at the interface,to organize a 3D conductive network.The unique scaffold structure provides more active sites and shortens the Na+diffusion path.Meanwhile,the structure exhibits excellent mechanical stability to alleviate the volume expansion during circulation.Furthermore,the Fe in Fe3O4/Fe heterojunction can adjust the d-band center of Fe in Fe3O4 to enhance the adsorption between Fe3O4 and Na2S intermediate,which restrains the shuttle effect.Therefore,the FHNCS demonstrates a high specific capacity of 436 mAh g-1 at 0.5 A g-1,84.7％and 73.4％of the initial capacities are maintained after 100 cycles at 0.5 A g-1 and 1000 cycles at 1.0 A g-1.We believe that this strategy gives an inspiration for constructing Fe-based anode with excellent rate capability and cycling stability.
查看更多>>摘要：Lithium metal batteries(LMBs)and anode-free LMBs(AFLMBs)present a solution to the need for batteries with a significantly superior theoretical energy density.However,their adoption is hindered by low Coulombic efficiency(CE)and rapid capacity fading,primarily due to the formation of unstable solid electrolyte interphase(SEI)layer and Li dendrite growth as a result of uneven Li plating.Here,we report on the use of a stoichiometric Ti3C2Tx(S-Ti3C2Tx)MXene coating on the copper current collector to enhance the cyclic stability of an anode-free lithium metal battery.The S-Ti3C2Tx coating provides abundant nucleation sites,thereby lowering the overpotential for Li nucleation,and promoting uniform Li plating.Additionally,the fluorine(-F)termination of S-Ti3C2Tx participates in the SEI formation,producing a LiF-rich SEI layer,vital for stabilizing the SEI and improving cycle life.Batteries equipped with S-Ti3C2Tx@Cu current collectors displayed reduced Li consumption during stable SEI formation,resulting in a significant decrease in capacity loss.AFLMBs with S-Ti3C2Tx@Cu current collectors achieved a high initial capacity density of 4.2 mAh cm 2,70.9％capacity retention after 50 cycles,and an average CE of 98.19％in 100 cycles.This innovative application of MXenes in the energy field offers a promising strategy to enhance the performance of AFLMBs and could potentially accelerate their commercial adoption.
查看更多>>摘要：As the persistent concerns regarding sluggish reaction kinetics and insufficient conductivities of sulfur cathodes in all-solid-state Li-S batteries(ASSLSBs),numerous carbon additives and solid-state electrolytes(SSEs)have been incorporated into the cathode to facilitate ion/electron pathways around sulfur.However,this has resulted in a reduced capacity and decomposition of SSEs.Therefore,it is worth exploring neotype sulfur hosts with electronic/ionic conductivity in the cathode.Herein,we present a hybrid cathode composed of few-layered S/MoS2/C nanosheets(＜5 layers)that exhibits high-loading and long-life performance without the need of additional carbon additives in advanced ASSLSBs.The multifunctional MoS2/C host exposes the abundant surface for intimate contacting sites,in situ-formed LixMoS2 during discharging as mixed ion/electron conductive network improves the S/Li2S conversion,and contributes extra capacity for the part of active materials.With a high active material content(S+MoS2/C)of 60 wt％in the S/MoS2/C/Li6PS5CI cathode composite(the carbon content is only～3.97 wt％),the S/MoS2/C electrode delivers excellent electrochemical performance,with a high reversible discharge capacity of 980.3 mAh g-1(588.2 mAh g-1 based on the whole cathode weight)after 100 cycles at 100 mA g-1.The stable cycling performance is observed over 3500 cycles with a Coulombic efficiency of 98.5％at 600 mA g1,while a high areal capacity of 10.4 mAh cm-2 is achieved with active material loading of 12.8 mg cm-2.
查看更多>>摘要：Grain boundaries(GBs)in perovskite polycrystalline films are the most sensitive place for the formation of the defect states and the accumulation of impurities.Thus,abundant works have been carried out to explore their properties and then try to solve the induced problems.Currently,two important issues remain.First,the role of GBs in charge carrier dynamics is unclear due to their component complexity/defect tolerance nature and the insufficiency in testing accuracy.Some works conclude that GBs are benign,while others consider GBs as carrier recombination centers.Things for sure are the deterioration in ion transport and perovskite decomposition.Second,to solve the known hazards of GBs,a lot of additives have been added to anchoring ions and passivate defects.But in most of those works,GBs and perovskite surfaces are treated in the same manner ignoring the fact that GB is essentially a homogeneous junction in a narrow and slender space,while surface is a heterogeneous junction with a stratified structure.In this review,we focus on works insight into GBs and additives for them.Additionally,we also discuss the prospects of the maturity of GB exploration toward upscaling the manufacture of perovskite photovoltaic and related optoelectronic devices.
查看更多>>摘要：Nickel oxide(NiOx)has been established as a highly efficient and stable hole-transporting layer(HTL)in perovskite solar cells(PSCs).However,existing deposition methods for NiOx have been restricted by high-vacuum processes and fail to address the energy level mismatch at the NiOx/perovskite interface,which has impeded the development of PSCs.Accordingly,we explored the application of NiOx as a hybrid HTL through a sol-gel process,where a NiOx film was pre-doped with Ag ions,forming a p/p+homojunction in the NiOx-based inverted PSCs.This innovative approach offers two synergistic advantages,including the enlargement of the built-in electric field for facilitating charge separation,optimizing energy level alignment,and charge transfer efficiency at the interface between the perovskite and HTL.Incorporating this hybrid HTL featuring the p/p+homojunction in the inverted PSCs resulted in a high-power conversion efficiency(PCE)of up to 19.25％,significantly narrowing the efficiency gap compared to traditional n-i-p devices.Furthermore,this innovative strategy for the HTL enhanced the environmental stability to 30 days,maintaining 90％of the initial efficiency.
查看更多>>摘要：Semitransparent organic solar cells show attractive potential in the application of building-integrated photovoltaics,agrivoltaics,floating photovoltaics,and wearable electronics,as their multiple functionalities of electric power generation,photopermeability,and color tunability.Design and exploration of semitransparent organic solar cells with optimal and balanced efficiency and average visible light transmittance and simultaneously high stability are in great demand.In this work,based on a layer-by-layer-processed active layer and an ultrathin metal electrode,inverted semitransparent organic solar cells(ITO/AZO/PM6/BTP-eC9/MoO3/Au/Ag)were fabricated.Optimal and balanced efficiency and average visible light transmittance were demonstrated,and simultaneously promising thermal and light stability were achieved for the obtained devices.The power conversion efficiency of 13.78-12.29％and corresponding average visible light transmittance of 14.58-25.80％were recorded for the ST-OSC devices with 25-15 nm thick Ag electrodes,respectively.Superior thermal and light stability with～90％and～85％of initial efficiency retained in 400 h under 85 ℃ thermal stress and AM1.5 solar illumination were demonstrated,respectively.
查看更多>>摘要：To unlock the full potential of PSCs,machine learning(ML)was implemented in this research to predict the optimal combination of mesoporous-titanium dioxide(mp-TiO2)and weight percentage(wt％)of phenyl-C61-butyric acid methyl ester(PCBM),along with the current density(Jsc),open-circuit voltage(Voc),fill factor(ff),and energy conversion efficiency(ECE).Then,the combination that yielded the highest predicted ECE was selected as a reference to fabricate PCBM-PSCs with nanopatterned TiO2 layer.Subsequently,the PCBM-PSCs with nanopatterned TiO2 layers were fabricated and characterized to further understand the effects of nanopatterning depth and wt％of PCBM on PSCs.Experimentally,the highest ECE of 17.338％is achieved at 127 nm nanopatterning depth and 0.10 wt％of PCBM,where the Jsc,Voc,and ff are 22.877 mA cm-2,0.963 V,and 0.787,respectively.The measured Jsc,Voc,ff,and ECE values show consistencies with the ML prediction.Hence,these findings not only revealed the potential of ML to be used as a preliminary investigation to navigate the research of PSCs but also highlighted that nanopatterning depth has a significant impact on Jsc,and the incorporation of PCBM on perovskite layer influenced the Voc and ff,which further boosted the performance of PSCs.
查看更多>>摘要：The high voltage required to overcome the thermodynamic threshold and the complicated kinetics of the water splitting reaction limit the efficiency of single semiconductor-based photoelectrochemistry.A semiconductor/solar cell tandem structure has been theoretically demonstrated as a viable path to achieve an efficient direct transformation of sunlight into chemical energy.However,compact designs exhibiting the indispensable optimally balanced light absorption have not been demonstrated.In the current work,we design and implement a compact tandem providing the complementary absorption of a highly transparent BiVO4 photoanode and a PM6:Y6 solar cell.Such bandgap combination approaches the optimal to reach the solar-to-hydrogen(STH)conversion upper limit for tandem photoelectrochemical cells(PECs).We demonstrate that,by using a photonic multilayer structure to adequately balance sunlight absorption among both tandem materials,a 25％increase in the bias-free STH conversion can be achieved,setting a clear path to take compact tandem PECs to the theoretical limit performance.
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