Deciphering the potassium storage phase conversion mechanism of phosphorus by combined solid-state NMR spectroscopy and density functional theory calculations

Phosphorus is the potential anode material for emerging potassium-ion batteries(PIBs)owing to the highest specific capacity and relatively low operation plateau.However,the reversible delivered capacities of phosphorus-based anodes,in reality,are far from the theoretical capacity corresponding to the formation of K3P alloy.And,their underlying potassium storage mechanisms remain poorly understood.To address this issue,for the first time,we perform high-resolution solid-state31P NMR combined with XRD measurements,and density functional theory calculations to yield a systemic quantitative understanding of(de)potassiation reaction mechanism of phosphorus anode.We explicitly reveal a previously unknown asymmetrical nanocrystalline-to-amorphous transition process via rP←→(K_(3)P_(11),K_(3)P_(7),beta-K_(4)P_(6))←→(alpha-K4P6)←→(K_(1-x)P,KP,K_(4-x)P3,K_(1+x)P)←→(amorphous K4P3,amorphous K3P)that are proceed along with the electrochemical potassiation/depotassiation processes.Additionally,the corresponding KP alloys intermediates,such as the amorphous phases of K_(4)P_(3),K_(3)P,and the nonstoichiometric phases of“K_(1-x)P”,“K_(1+x)P”,“K_(4-x)P_(3)”are experimentally detected,which indicating various complicated K-P alloy species are coexisted and evolved with the sluggish electrochemical reaction kinetics,resulting in lower capacity of phosphorus-based anodes.Our findings offer some insights into the specific multi-phase evolution mechanism of alloying anodes that may be generally involved in conversion-type electrode materials for PIBs.

Electromechanical Properties of Microcantilever Actuated by Enhanced Piezoelectric PZT Thick Film

Pb (有 0.8 μm， 2 μm 和 4 μm 的厚度的 Zr 0.53, Ti 0.47)O3(PZT ) 电影被一个大音阶的第五音胶化方法准备，他们的纵的压电的系数被分析。结果证明 PZT 厚电影，其密度接近体积 PZT，有更好的结晶化，与 d， PZT 的 33 和比那些大得多的密度变瘦电影。一部 4-μm-thick PZT 电影激活的压电的微伸臂被制作，它的排水量在不同频率和电压被测量。排水量增加线性地为 5V 偏爱在 30kHz 与增加的偏爱，和 0.544 μm 的最大的排水量被观察。反响的频率与理论结果在实验火柴获得了相当好，并且 PZT 微伸臂的反响的频率能被控制并且建立，这被显示出。

Enhanced piezoelectric properties of Nd^(3+) doped nano-lead zirconate titanate piezoelectric ceramics

Nd3+ doped lead zirconate titanate (Pb1-3x/2NdxZr0.52Ti0.48O3, PNZT) nanopowders were prepared through a modified sol-gel method. The effects of Nd3+ doping on the microstructures and properties of PNZT ceramics have been studies. The grain sizes of the perovskite PNZT nanopowders were about 100nm and the lattice distortion of the PNZT increased with the content of Nd3+ up to 9 mol%. The dopant of Nd3+ resulted in the decrease of crystal lattice parameter a and the obvious increase of c and c/a, which effectively improved the sintered densification and activity of the PNZT ceramics. Due to lead vacancies caused by the doping of Nd3+ in the PZT, the piezoelectric constant, electromechanical coupling coefficient and dielectric constant observed were much higher than the monolithic PZT.

Strain-magnetization property of Ni-Mn-Ga(Co,Cu) microwires

Magnetization associated with reversible phase transformation or rearrangement of martensite variants of two kinds of shape memory alloys under the coupling of tensile stress were investigated.One is the austenitic Ni_(46)Mn_(28)Ga_(20)Co_(3)Cu_(3)micro wire with the [001] preferred orientation,which exhibits enhanced cyclic stability and large fully recoverable strain(> 8%) due to the stress-induced reversible martensitic transformation at room temperature.The other is the Ni_(54)Mn_(24)Ga_(22)microwire with ferromagnetic martensitic phase,which has preferential orientation and also exhibits large tensile strain.Based on the improved mechanical properties,the strain-magnetization effect of the two kinds of microwire under the coupling of orthogonal magnetic field and tensile stress was performed and the results indicate that the magnetization decreases with the increase of tensile strains.Furthermore,the magnetization mechanism related to the magnetostructural evolution under stress-magnetic coupling was discussed.This study provides a new way for smart magnetic microwires for novel non-contact and non-destructive detection.

Helium Bubble Growth in He^(+) Ions Implanted 304L Stainless Steel Processed by Laser Powder Bed Fusion During Post-Irradiation Annealing at 600℃

The abundancy of defect sinks in the microstructure of laser powder bed fusion(LPBF) processed austenitic stainless steels was found to be beneficial for helium resistance.In the current study,the influence of the novel microstructure in LPBF processed 304 L on the helium bubble growth behaviour was investigated using transmission electron microscopy in samples implanted with He^(+) ion and post-irradiation annealing treated at 600℃ for 1 h.Two variants of LPBF processed 304 L samples were used,one in as-built condition and the other solution-annealed.The comparison between the two samples indicated that the helium bubble growth was inhibited and remained stable in the as-built sample but coarsened significantly in the solution-annealed sample.The sub-grain boundaries and oxide nano-inclusions acted as defect sinks to trap helium atoms and inhibited the growth of helium bubble in the as-built sample under the post-irradiation annealing conditions used.

Solar-Powered Environmentally Friendly Hydrogen Production:Advanced Technologies for Sunlight-Electricity-Hydrogen Nexus

Hydrogen production from water splitting is a clean and sustainable hydrogen production route to alleviate the current energy crisis.However,factors such as energy conversion efficiency,cost-effectiveness,and social benefit limit their industrial application.Therefore,the development of advanced water splitting technologies using clean and renewable energy has become an important research goal of the world.Converting endless solar energy into hydrogen energy directly or indirectly is an effective way to reduce the energy input of hydrogen production.This review focuses on the latest advances in the coupling design of renewable energy supply devices and catalytic electrodes in hydrogen production systems.We not only review the single hydrogen production system based on photochemical,photoelectrochemical,photovoltaic,thermoelectric,pyroelectric,and piezoelectric devices,but also discuss the complex systems of the multiple devices.The structural design of energy supply devices and catalytic electrodes and the study of hydrogen production performance in different systems will be critically discussed in this work.Finally,current challenges and future perspectives of advanced technologies for sunlight-electricity-hydrogen nexus are also presented.It is hoped that this review will provide a timely reference for advancing the development of sunlight-electricity-hydrogen nexus and thus achieve the goal of sustainable production of green hydrogen.