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As the most promising anodic candidate for alkali ion batteries, red phosphorus (P) still faces big challenges, such as the poor rate and cycling performance, which are caused by the insulative nature and the large volume change throughout the alloy/dealloy process. To ameliorate above issues, the traditional way is confining P into the carbon host. However, investigations on maximizing P utilization are inadequate; in other words, how to achieve entire confinement with a high loading amount is still a problem. Additionally, the application of P in potassium-ion batteries (PIBs) is in its infant stage, and the corresponding potassiation product is controversial. Herein, a nitrogen-doped stripped-graphene CNT (N-SGCNT) as carbon framework is prepared to exclusively confine ultrafine P to construct P@N-SGCNT composites. Benefitting from the in situ cross-linked structure, N-SGCNT loaded with 41.2 wt % P (P2@N-SGCNT) shows outstanding Na+/K+ storage performance. For instance, P2@N-SGCNT exhibits high reversible capacities of 2480 mAh g-1 for sodium-ion batteries (SIBs) and 762 mAh g-1 for PIBs, excellent rate capabilities of 1770 mAh g-1 for SIBs and 354 mAh g-1 for PIBs at 2.0 A g-1, and long cycling stability (a capacity of 1936 mAh g-1 after 2000 cycles for SIBs and 319 mAh g-1 after 1000 cycles for PIBs). Furthermore, due to this exclusively confined P structure, the K+ storage mechanism with the end product of K4P3 has been identified by experimental and theoretical results.

All-solid-state lithium-ion batteries (ASSLIBs) are receiving tremendous attention for safety concerns over liquid system. However, current ASSLIBs still suffer from poor cycling and rate performance because of unfavorable interfacial contact between solid electrolyte and electrodes, especially in the alloy-based anode. To wet the solid electrode/electrolyte interface, accommodate volume change, and further boost kinetics, liquid metal Ga is introduced into the representative Sb anode, and its corresponding role is comprehensively revealed by experimental results and theoretical calculations for the first time. In addition to interface contact and strain accommodation, with the aid of in situ generation of liquid metal Ga, the lithiation/de-lithiation activity of Sb is stimulated, showing outstanding rate and cycling performance in half cells. Furthermore, benefited from the in situ chemical reaction, TiS

Magnesium-based hydrides are promising hydrogen storage materials; however, little progress has been achieved in improving hydrogen storage performance under ambient conditions, consequently impeding further commercial application. Herein, a lithium rich transition metal oxide, Li3VO4 has been employed to catalyze the hydrogen storage reaction of magnesium-based hydrides, enabling a fast and full hydrogenation of Mg at lower temperatures. The structural stability of Li3VO4 upon de/rehydrogenation reactions has been confirmed by neutron diffraction and transmission electron microscope observations. The synergistic catalytic role of Li3VO4 has elucidated that the existence of Li stimulates the catalytic activity of V and simultaneously suppresses the activity of O. V is the key catalytically active site, while O can react with active Mg to generate MgO which is a passivation layer and could prevent the diffusion of H. These findings will give an opportunity for the use of other lithium rich transition metal oxides in the field of catalyzing hydrogen storage systems.

Since the discovery of metal hydrides as a conversion-type anode in lithium-ion batteries in 2008, many metal hydrides have been investigated for lithium-ion battery anodes. Although much progress has been made, metal hydrides still face severe challenges such as poor first cycle reversibility, low electrical conductivity, and high reactivity with liquid electrolyte. Here we demonstrate a three-dimensional hierarchical metal hydride/graphene composite (LiNa2AlH6/3DG) that shows the best performance among reported metal hydride anodes. LiNa2AlH6 nanoparticles are uniformly anchored on graphene nanosheets which self-assemble into the 3D microflowers hierarchical structure, and exhibit outstanding cycling stability with LiBH4 as a solid electrolyte. An ultra-high capacity of 861 mA h g−1 at the current density of 5 A g−1 and a long cycle life of 500 cycles with capacity retention of 97% are demonstrated. These findings pave the way for designing nanoscale metal hydrides as electrode materials in solid-state lithium batteries.

Lithium dendrites (filaments) propagation in the solid electrolyte (SEs) leading to short circuits is one of the biggest obstacles to the application of all-solid-state lithium metal batteries (ASSLMBs). Due to the lacking of operando techniques that can provide nano-scale spatial resolution, the insufficient knowledge of the lithium dendrite growth inside SEs makes it difficult to suppress dendrite formation. To reveal the mechanism of Li filament growth in SEs, we achieved real-time monitoring of the nanoscale Li filament growth by operando small-angle neutron scattering (SANS) in a Cu|LLZNO|Li cell. On continuous plating, Li filament growth is not simply an accumulation of Li, but there is a dynamic evolution due to the competition between Li filament formation and self-healing. This dynamic evolution of Li filaments has been proved to be prevalent in typical SEs. With the aid of simulations and experiments, this dynamic competition was demonstrated to be highly dependent on the temperature variation. The enhanced self-healing ability of Li at elevated temperatures plays a positive role in suppressing Li filament formation. The cycle life of the cell was improved by heat therapy, which provided a brand-new insight for suppressing Li filament formation. Operando SANS with high Li sensitivity and high spatial resolution provides a new platform for investigating Li filaments in SEs.

A newly-developed in situ neutron diffraction method has been employed to search elastic tension induced lattice distortions in DD10 single crystal nickel-based superalloy under tensile condition of 500 °C/760 MPa. Multiple lattice reflections, viz., {002}, {003}, {220}, {311} were in situ measured. Two samples which were stretched along [001] direction and 18° deviation of [001] direction, respectively, were measured for comparison. As samples were heated to 500 °C, the lattice stress of both samples gradually relaxes. With 760 MPa tension applied, the response of reflections of γ and γ’ phases were anisotropic. Compared with 0° sample, 18° sample resulted in distinguishable results. Due to the large extra stress, the mismatch along [001] direction is much negative, whereas that perpendicular to [001] get slightly positive. Owing to the different stress states, γ phase is divided into two conditions. The tetragonal distortion with c/a of γ⊥ channel is largest, while that of γ’ phase is small. The distortions at γ/γ’ phase boundary result in broadening the boundary of γ’ phase. In this work, a new elastic-induced lattice distortion model that enhances apprehensions to the constraint effect between γ and γ’ phases is built, which might provide the directly experimental evidence to the origin of rafting.

The extended application of sodium ion batteries (SIBs) to cold climates or high-altitude areas has been severely impeded by the sluggish solid-diffusion process of Na+ in the anode material. Herein, we for the first time report CoGa2S4 as a novel anode material for SIBs, exhibiting superior full cell performance when coupled with a high-voltage Na0.7[Mn0.6Ni0.2Mg0.2]O2 (NMN-2) cathode in a voltage range of 1.0–4.1 V. More importantly, when tested at an ultra-low temperature of −60 °C, CoGa2S4 delivers a high reversible capacity close to 100 mA h g−1 upon 1000 cycles at a current density of 1 A g−1. This excellent low-temperature performance is attributed to the fact that after the first discharge process of the CoGa2S4 electrode, the Ga-based sulfide loses its electrochemical reaction activity, but fortunately it can serve as a high ionic conductivity medium, facilitating the conversion reaction of cobalt sulfides. The phenomenon that the Ga-based sulfide in CoGa2S4 sacrifices the capacity, but allows cobalt sulfides to withstand temperature variation sheds light on designing high performance sub-zero temperature anodes for SIBs.

Developing sodium ion battery (SIB) anode materials of a low-cost and high-capacity nature for future large-scale applications still involves challenges. Herein, we have reported gallium sulfide (Ga2S3) as a novel SIB anode material for the first time. Ga2S3 nanorods have been synthesized via the facile hydrothermal preparation of a GaOOH precursor with subsequent H2S annealing. Mixed with graphene upon electrode preparation, this Ga2S3 electrode maintains a reversible specific capacity of 476 mA h g−1 after 100 cycles at a current density of 0.4 A g−1, with a coulombic efficiency of over 99%. Ex situ XRD analysis and theoretical calculations are employed to comprehensively elucidate the detailed sodium ion storage mechanism of Ga2S3, which is composed of initial Na+ intercalation, a subsequent multi-step conversion reaction between S and Na+, and an eventual alloying reaction between Ga and Na+ with the end product of Na7Ga13. Further kinetics analysis has demonstrated that the conversion reaction is the rate-limiting step due to a multi-step reaction with the intermediate phase of GaS. Moreover, the appearance of liquid metal Ga, as confirmed via TEM observations and theoretical calculations, can serve as a self-healing agent that repairs cracks in the electrode. Our findings shed light on the further design of Ga-based materials, and they also can be extended to solid-state-battery systems.

The present work attempts to reveal the correlation between the microstructural defects and residual stress in the single crystal nickel-based superalloy, both of which play the significant role on properties and performance. Neutron diffraction was employed to investigate the microstructural defects and residual stresses in a single crystal (SC) nickel-based superalloy, which was subjected to creeping under 220 MPa and 1000 °C for different times. The measured superlattice and fundamental lattice reflections confirm that the mismatch and tetragonal distortions with c/a > 1 exist in the SC superalloy. At the initially unstrained state, there exists the angular distortion between γ and γ’ phases with small triaxial compressive stresses, ensuring the structural stability of the superalloy. After creeping, the tetragonal distortion for the γ phase is larger than that for the γ’ phase. With increasing the creeping time, the mismatch between γ and γ’ phases increases to the maximum, then decreases gradually and finally remains unchanged. The macroscopic residual stress shows a similar behavior with the mismatch, indicating the correlation between them. Based on the model of shear and dislocations, the evolution of microstructural defects and residual stress are reasonably explained. The effect of shear is dominant at the primary creep stage, which greatly enlarges the mismatch and the residual stress. The dislocations weaken the effect of shear for the further creep stage, resulting in the decrease of the mismatch and relaxation of the residual stress. Those findings add some helpful understanding into the microstructure-performance relationship in the SC nickel-based superalloy, which might provide the insight to materials design and applications.

Developing sodium ion battery (SIB) anode materials of a low-cost and high-capacity nature for future large-scale applications still involves challenges. Herein, we have reported gallium sulfide (Ga2S3) as a novel SIB anode material for the first time. Ga2S3 nanorods have been synthesized via the facile hydrothermal preparation of a GaOOH precursor with subsequent H2S annealing. Mixed with graphene upon electrode preparation, this Ga2S3 electrode maintains a reversible specific capacity of 476 mA h g-1 after 100 cycles at a current density of 0.4 A g-1, with a coulombic efficiency of over 99%. Ex situ XRD analysis and theoretical calculations are employed to comprehensively elucidate the detailed sodium ion storage mechanism of Ga2S3, which is composed of initial Na+ intercalation, a subsequent multi-step conversion reaction between S and Na+, and an eventual alloying reaction between Ga and Na+ with the end product of Na7Ga13. Further kinetics analysis has demonstrated that the conversion reaction is the rate-limiting step due to a multi-step reaction with the intermediate phase of GaS. Moreover, the appearance of liquid metal Ga, as confirmed via TEM observations and theoretical calculations, can serve as a self-healing agent that repairs cracks in the electrode. Our findings shed light on the further design of Ga-based materials, and they also can be extended to solid-state-battery systems.