Crystal phase regulations may endow materials with enhanced or new functionalities. However, syntheses of noble metal-based allomorphic nanomaterials are extremely difficult, and only a few successful examples have been found. Herein, we report the discovery of hexagonal close-packed Pt–Ni alloy, despite the fact that Pt–Ni alloys are typically crystallized in face-centred cubic structures. The hexagonal close-packed Pt–Ni alloy nano-multipods are synthesized via a facile one-pot solvothermal route, where the branches of nano-multipods take the shape of excavated hexagonal prisms assembled by six nanosheets of 2.5 nm thickness. The hexagonal close-packed Pt–Ni excavated nano-multipods exhibit superior catalytic property towards the hydrogen evolution reaction in alkaline electrolyte. The overpotential is only 65 mV versus reversible hydrogen electrode at a current density of 10 mA cm−2, and the mass current density reaches 3.03 mA μgPt−1 at −70 mV versus reversible hydrogen electrode, which outperforms currently reported catalysts to the best of our knowledge.

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Metallic Zn is believed to be an ideal anode for aqueous batteries, but its reversibility is deteriorated by noncompact and dendritic Zn deposition along with interfacial parasitic reactions. Herein, it is reported that introducing cholinium (Ch + ) cations into aqueous electrolytes enables a spatially compact, non-dendritic, and corrosion-free Zn electrode even at high areal capacity (5.0 and 10.0 mAh cm -2 ) using a pressure-free electrolytic cell. This strategy is applicable to various Zn-salt-based aqueous electrolytes (e.g., 1 M ZnSO 4 , Zn(CH 3 COO) 2 , and ZnCl 2 ). It is found that bulky Ch + cations create a "leveling effect" to homogenize Zn deposition and render an H 2 O poor electrical double layer near Zn by favorably absorbing on the Zn surface. Moreover, Ch + cations with -OH group disrupt the original H-bonded network of water to reduce H 2 O-induced side reactions and promote the Zn 2+ de-solvation by forming H-bond with H 2 O. As a result, the Zn electrode in the optimized 1 M ZnSO 4 with 4 M Ch + electrolyte manifests remarkable electrochemical performances involving high Coulombic efficiency of 99.6% in Zn//Cu cell and prolonged cycling stability over 2000 h in Zn//Zn cell (1.0 mA cm -2 , 1.0 mAh cm -2 ). This work provides a new strategy for the design of compact and dendrite-free Zn battery chemistry.

In this work, the Li-rich oxide Li1.23Ni0.09Co0.12Mn0.56O2 was synthesized through a facile route called aqueous solution-evaporation route that is simple and without waste water. The as-prepared Li1.23Ni0.09Co0.12Mn0.56O2 oxide was confirmed to be a layered LiMO2-Li2MnO3 solid solution through ex situ X-ray diffraction (ex situ XRD) and transmission electron microscopy (TEM). Electrochemical results showed that the Li-rich oxide Li1.23Ni0.09Co0.12Mn0.56O2 material can deliver a discharge capacity of 250.8 mAhg(-1) in the 1st cycle at 0.1 C and capacity retention of 86.0% in 81 cycles. In situ X-ray diffraction technique (in situ XRD) and ex situ TEM were applied to study structural changes of the Li-rich oxide Li1.23Ni0.09Co0.12Mn0.56O2 material during charge-discharge cycles. The study allowed observing experimentally, for the first time, the existence of β-MnO2 phase that is appeared near 4.54 V in the first charge process, and a phase transformation of the β-MnO2 to layered Li0.9MnO2 is occurred in the initial discharge process by evidence of in situ XRD pattrens and selected area electron diffraction (SAED) patterns at different states of the initial charge and discharge process. The results illustrated also that the variation of the in situ X-ray reflections during charge-discharge cycling are clearly related to the changes of lattice parameters of the as-prepared Li-rich oxide during the charge-discharge cycles.

Crystallography modulation of zinc (Zn) metal anode is promising to promote Zn reversibility in aqueous electrolytes, but efficiently constructing Zn with specific crystallographic texture remains challenging. Herein, we report a current‐controlled electrodeposition strategy to texture the Zn electrodeposits in conventional aqueous electrolytes. Using the electrolytic cell with low‐cost Zn(CH3COO)2 electrolyte and Cu substrate as a model system, the texture of as‐deposited Zn gradually transforms from (101) to (002) crystal plane as increasing the current density from 20 to 80 mA cm−2. Moreover, the high current accelerates the Zn nucleation rate with abundant nuclei, enabling uniform deposition. The (002) texture permits stronger resistance to dendrite growth and interfacial side reactions than the (101) texture. The resultant (002)‐textured Zn electrode achieves deep cycling stability and supports the stable operation of full batteries with conventional V/Mn‐based oxide cathodes.

The nickel-rich layered oxide materials have been selected as promising cathode materials for the next generation lithium ion batteries because of their large capacity and comparably high operating voltage. However, at high voltage (beyond 4.30 V vs Li/Li), the members of this family are all suffering from a rapid capacity decay, which was commonly concerned with crystal lattice distortion and related cation disordering. In this work, the quasi-spherical Ni-rich layered LiNiCoMnO (QS-NMC622) material was successfully synthesized through the carbonate co-precipitation method. A coupled measurement, which is a combination of potentiostatic intermittent titration technique (PITT) and in situ X-ray diffraction (XRD), was deployed to simultaneously capture the structural changes and lithium ion diffusion coefficient of QS-NMC622 material during the first cycle. With help of in situ XRD patterns and high-resolution transmission electron microscope (HR-TEM) images, a defective spinel framework of Fd3̅m space group was detected along with a rapid decreasing lattice-parameter c and lattice distortion at deep delithiated state, which causes poor kinetics related to lithium ion mobility. The new-born framework seems to transform and remain as full spinel structure in the parent phase to the end of charge/discharge with high voltage, which could deteriorate both the surface and body structure stability during the subsequent cycles. This established coupled in situ measurement could be applied to simultaneously investigate the structure transformation and kinetics of cathode materials during charge/discharge.

Owing to high specific capacity of ∼250 mA h g, lithium-rich layered oxide cathode materials (LiNi CoMnO) have been considered as one of the most promising candidates for the next-generation cathode materials of lithium ion batteries. However, the commercialization of this kind of cathode materials seriously restricted by voltage decay upon cycling though Li-rich materials with high cobalt content have been widely studied and show good capacity. This research successfully suppresses voltage decay upon cycling while maintaining high specific capacity with low Co/Ni ratio in Li-rich cathode materials. Online continuous flow differential electrochemical mass spectrometry (OEMS) and in situ X-ray diffraction (XRD) techniques have been applied to investigate the structure transformation of Li-rich layered oxide materials during charge-discharge process. The results of OEMS revealed that low Co/Ni ratio lithium-rich layered oxide cathode materials released no lattice oxygen at the first charge process, which will lead to the suppression of the voltage decay upon cycling. The in situ XRD results displayed the structure transition of lithium-rich layered oxide cathode materials during the charge-discharge process. The LiNiMnO cathode material exhibited a high initial medium discharge voltage of 3.710 and a 3.586 V medium discharge voltage with the lower voltage decay of 0.124 V after 100 cycles.

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