Although chalcogenide anodes possess higher potassium storage capacity than intercalated-based graphite,their drastic volume change and the irreversible electrochemical reactions still hinder the effective electron/io...Although chalcogenide anodes possess higher potassium storage capacity than intercalated-based graphite,their drastic volume change and the irreversible electrochemical reactions still hinder the effective electron/ion transfer during the potassiation/depotassiation process.To solve the above problems,this article proposes the synthesis of a lamellar nanostructure where graphene nanosheets are embedded with SnSb_(2)Se_(4)nanoparticles(SnSb_(2)Se_(4)/GNS).In the product,fine monodisperse SnSb_(2)Se_(4)nanoparticles are coupled with graphene nanosheets to form a porous network framework,which can effectively mitigate the drastic volume changes during electrode reactions and guarantee efficient potassium-ion storage through the synergistic interactions among multiple elements.Various electrochemical analyses prove that SnSb_(2)Se_(4)inherits the advantages of the binary Sb2Se3 and SnSe while avoiding their disadvantages,confirming the synergistic effect of the ternary–chalcogenide system.When tested for potassium storage,the obtained composite delivers a high specific capacity of 368.5 mAh g^(-1)at 100 mA g^(-1)and a stable cycle performance of 265.8 mAh g^(-1)at 500 mA g^(-1)over 500 cycles.Additionally,the potassium iron hexacyanoferrate cathode and the SnSb_(2)Se_(4)/GNS anode are paired to fabricate the potassium-ion full cell,which shows excellent cyclic stability.In conclusion,this strategy employs atomic doping and interface interaction,which provides new insights for the design of high-rate electrode materials.展开更多
As a typical (IV–VI)_(x)(V_(2)VI_(3))_(y) compound, the tetradymite-like layered SnSb_(2)Te_(4) -based compounds have attracted increasing attention in the thermoelectric community owing to the intrinsically low latt...As a typical (IV–VI)_(x)(V_(2)VI_(3))_(y) compound, the tetradymite-like layered SnSb_(2)Te_(4) -based compounds have attracted increasing attention in the thermoelectric community owing to the intrinsically low lattice thermal conductivity. Nevertheless, the effect of cations disorder on the inherent physical characteristics remains puzzling, and its inferior Seebeck coefficient is the bottleneck to achieving high thermoelectric performance. In this work, the thermoelectric properties of polycrystalline In_(x)Sn_(1−x)Sb_(2)(Te_(1−y)Se_(y))_(4) (0≤x≤0.1,0≤y≤0.15) samples are comprehensively investigated. In conjunction with the calculated band structure and experimental results, the Seebeck coefficient and power factor are markedly improved after the introduction of indium and selenium, which originates from the combined effects of the emergent resonant states and converged valence bands along with optimal carrier concentration. Additionally, compared with the ordered lattice structure, the disordered cations occupancy in SnSb_(2)Te_(4) further strengthens lattice anharmonicity and reduces phonon group velocity verified by first-principles calculations, securing intrinsically low lattice thermal conductivity. Finally, a record zT value of ∼0.6 at 670 K and an average zT of ∼0.4 between 320 and 720 K are obtained in the In0.1 Sn0.9 Sb2 Te3.4 Se0.6 sample, being one of the highest zT values among SnSb2 Te4 -based materials. This work not only demonstrates that SnSb2 Te4 -based compounds are promising thermoelectric candidates, but also provides guidance for the promotion of thermoelectric performance in a broad temperature range.展开更多
With practical electrocatalytic hydrogen production frequently involving the splitting of water in various pH media,there is an urgent need but still a technical challenge to develop low-cost,highly active,and stable ...With practical electrocatalytic hydrogen production frequently involving the splitting of water in various pH media,there is an urgent need but still a technical challenge to develop low-cost,highly active,and stable electrocatalysts for pH-universal hydrogen evolution reaction(HER).We report herein the adoption of a hydrothermal reaction combined with a post gas-phase doping strategy to fabricate P-doped NiCo_(2)Se_(4) hollow nanoneedle arrays on carbon fiber paper(i.e.,P-NiCo_(2)Se_(4)/CFP).Notably,the optimal arrays(P8.71-NiCo_(2)Se_(4)/CFP)can afford an outstanding pH-universal HER performance,with an overpotential as low as 33,57,and 69 mV at 10 mA·cm^(−2) and corresponding Tafel slopes down to 52,61,and 72 mV·dec^(−1) in acidic,alkaline,and neutral media,respectively,outperforming most state-of-the-art nonprecious catalysts and even the commercial Pt/C catalyst in both neutral and alkaline media at large current densities.Impressively,P_(8.71-)NiCo_(2)Se_(4)/CFP also displays good durability toward long-time stability testing in harsh acidic and alkaline electrolytes.Experimental and theoretical studies further reveal that the doping of P atoms into NiCo_(2)Se_(4) can simultaneously optimize its H*adsorption/desorption energy,water adsorption energy,and water dissociation energy by adjusting the local electronic states of various active sites,thus accelerating the rate-determining step of HER in different pH media to endow P-NiCo_(2)Se_(4) with an outstanding pH-universal HER performance.This work provides atomic-level insights into the roles of active sites in various electrolysis environments,thereby shedding new light on the rational design of highly efficient pH-universal nonprecious catalysts for HER and beyond.展开更多
基金supported by the National Natural Science Foundation of China(22075147 and 22179063)
文摘Although chalcogenide anodes possess higher potassium storage capacity than intercalated-based graphite,their drastic volume change and the irreversible electrochemical reactions still hinder the effective electron/ion transfer during the potassiation/depotassiation process.To solve the above problems,this article proposes the synthesis of a lamellar nanostructure where graphene nanosheets are embedded with SnSb_(2)Se_(4)nanoparticles(SnSb_(2)Se_(4)/GNS).In the product,fine monodisperse SnSb_(2)Se_(4)nanoparticles are coupled with graphene nanosheets to form a porous network framework,which can effectively mitigate the drastic volume changes during electrode reactions and guarantee efficient potassium-ion storage through the synergistic interactions among multiple elements.Various electrochemical analyses prove that SnSb_(2)Se_(4)inherits the advantages of the binary Sb2Se3 and SnSe while avoiding their disadvantages,confirming the synergistic effect of the ternary–chalcogenide system.When tested for potassium storage,the obtained composite delivers a high specific capacity of 368.5 mAh g^(-1)at 100 mA g^(-1)and a stable cycle performance of 265.8 mAh g^(-1)at 500 mA g^(-1)over 500 cycles.Additionally,the potassium iron hexacyanoferrate cathode and the SnSb_(2)Se_(4)/GNS anode are paired to fabricate the potassium-ion full cell,which shows excellent cyclic stability.In conclusion,this strategy employs atomic doping and interface interaction,which provides new insights for the design of high-rate electrode materials.
基金financially supported in part by the National Natural Science Foundation of China(Grant Nos.52125103,52071041,U21A2054,12204080,11904039,and 12004060)supported in part by the Scientific and Technological Research Program of Chongqing Municipal Education Commission(GrantNo.KJQN202200623)the Natural Science Foundation of Chongqing(Grant No.CSTB2022NSCQ-MSX0382)。
文摘As a typical (IV–VI)_(x)(V_(2)VI_(3))_(y) compound, the tetradymite-like layered SnSb_(2)Te_(4) -based compounds have attracted increasing attention in the thermoelectric community owing to the intrinsically low lattice thermal conductivity. Nevertheless, the effect of cations disorder on the inherent physical characteristics remains puzzling, and its inferior Seebeck coefficient is the bottleneck to achieving high thermoelectric performance. In this work, the thermoelectric properties of polycrystalline In_(x)Sn_(1−x)Sb_(2)(Te_(1−y)Se_(y))_(4) (0≤x≤0.1,0≤y≤0.15) samples are comprehensively investigated. In conjunction with the calculated band structure and experimental results, the Seebeck coefficient and power factor are markedly improved after the introduction of indium and selenium, which originates from the combined effects of the emergent resonant states and converged valence bands along with optimal carrier concentration. Additionally, compared with the ordered lattice structure, the disordered cations occupancy in SnSb_(2)Te_(4) further strengthens lattice anharmonicity and reduces phonon group velocity verified by first-principles calculations, securing intrinsically low lattice thermal conductivity. Finally, a record zT value of ∼0.6 at 670 K and an average zT of ∼0.4 between 320 and 720 K are obtained in the In0.1 Sn0.9 Sb2 Te3.4 Se0.6 sample, being one of the highest zT values among SnSb2 Te4 -based materials. This work not only demonstrates that SnSb2 Te4 -based compounds are promising thermoelectric candidates, but also provides guidance for the promotion of thermoelectric performance in a broad temperature range.
基金supported by the National Natural Science Foundation of China(Nos.21872011 and 21273020).
文摘With practical electrocatalytic hydrogen production frequently involving the splitting of water in various pH media,there is an urgent need but still a technical challenge to develop low-cost,highly active,and stable electrocatalysts for pH-universal hydrogen evolution reaction(HER).We report herein the adoption of a hydrothermal reaction combined with a post gas-phase doping strategy to fabricate P-doped NiCo_(2)Se_(4) hollow nanoneedle arrays on carbon fiber paper(i.e.,P-NiCo_(2)Se_(4)/CFP).Notably,the optimal arrays(P8.71-NiCo_(2)Se_(4)/CFP)can afford an outstanding pH-universal HER performance,with an overpotential as low as 33,57,and 69 mV at 10 mA·cm^(−2) and corresponding Tafel slopes down to 52,61,and 72 mV·dec^(−1) in acidic,alkaline,and neutral media,respectively,outperforming most state-of-the-art nonprecious catalysts and even the commercial Pt/C catalyst in both neutral and alkaline media at large current densities.Impressively,P_(8.71-)NiCo_(2)Se_(4)/CFP also displays good durability toward long-time stability testing in harsh acidic and alkaline electrolytes.Experimental and theoretical studies further reveal that the doping of P atoms into NiCo_(2)Se_(4) can simultaneously optimize its H*adsorption/desorption energy,water adsorption energy,and water dissociation energy by adjusting the local electronic states of various active sites,thus accelerating the rate-determining step of HER in different pH media to endow P-NiCo_(2)Se_(4) with an outstanding pH-universal HER performance.This work provides atomic-level insights into the roles of active sites in various electrolysis environments,thereby shedding new light on the rational design of highly efficient pH-universal nonprecious catalysts for HER and beyond.
