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Abstract: The mechanical properties of graphene may be strongly affected by defects. In our work, the effects of the orientation and tilting angles of Stone–Thrower–Wales (STW, 5-7-7-5) defects on the mechanical properties of graphene have been investigated based on molecular dynamics simulations. When there is one centred STW defect including STW-1 defect and STW-2 defect, our study reveals that the orientation with respect to the chirality governs the mechanical properties of graphene. For STW-1 defective graphene, the strength of the armchair direction is much lower than that of zigzag direction. While the circumstance for STW-2 defective graphene is opposite, the strength of the armchair direction is much higher than the strength of the zigzag direction. Furthermore, when there is more than one STW defect, the mechanical properties of graphene depends on the tilting angle of STW defects. The breaking strength of graphene decreases with the increasing tilting angle. Our present work could provide significant insights into the effect of STW defects on the mechanical properties of graphene. [Copyright &y& Elsevier]

The failure phenomena of the full cell battery based on Li 1.5 Al 0.5 Ge 1.5 (PO 4) 3 ceramic electrolytes generally manifests as the macroscopic fading of the capacity, the governing mechanisms in the particular term of electrolytes remain elusive. In this study, Li 1.5 Al 0.5 Ge 1.5 (PO 4) 3 electrolytes after cycling are characterized by multiscale techniques, including Scanning Probe Microscopy, to systematically investigate the chemical and structural evolution processes. Secondary phases are proven to exist in the cycled Li 1.5 Al 0.5 Ge 1.5 (PO 4) 3. It is demonstrated that the Li 1.5 Al 0.5 Ge 1.5 (PO 4) 3 electrolytes suffer from both electrochemical and mechanical deterioration during the cycling processes. The changes in both chemical compositional and inhomogeneous mechanical stress result in the failure of the electrolyte and pose high resistance to lithium-ion transport. Furthermore, the ionic transport process is successfully manipulated by a local electric field with amplitude of 2 V and 4 V from the tiny tip in Scanning Probe Microscopy. Based on the observed electrochemical strain response and contact stiffness variation induced by dynamic Li-ion fluctuation under an applied AC electrical field, the degradation process of the Li 1.5 Al 0.5 Ge 1.5 (PO 4) 3 electrolyte is studied. It is determined that the chemo-mechanical degradation originates from the non-uniform Li ion distribution at the boundaries and/or voids in the interior of the electrolyte. • LAGP solid electrolytes after cycling are characterized by various techniques. • Secondary phases are proven to exist in the cycled LAGP solid electrolyte. • LAGP suffer from both electrochemical and mechanical deterioration after cycling. • Ionic transport process is successfully manipulated using SPM techniques. [ABSTRACT FROM AUTHOR]

We report effectiveness of dopants selected from group 13, such as B, Ga, and In, on the conductivity of Li1.5Al0.5Ge1.5(PO4)3 (LAGP) that is recognized as one of the promising solid electrolytes for next-generation solid-state lithium batteries. To minimize loss of versatile element, crystallization of LAGP using a microwave irradiation is introduced. Experimental results demonstrate that B enhances grain boundary conductivity, while Ga improves the bulk ionic conductivity. Co-doping of B and Ga leads to enhanced total ionic conductivity and remarkably reduced activation energy. [ABSTRACT FROM AUTHOR]

In hunting for safe and cost‐effective materials for post‐Li‐ion energy storage, the design and synthesis of high‐performance solid electrolytes (SEs) for all‐solid‐state batteries are bottlenecks. Many issues associated with chemical stability during processing and storage and use of the SEs in ambient conditions need to be addressed. Now, the effect of water as well as oxyhdryl group (.OH) on NaBi3O4Cl2 are investigated by evaluating ionic conductivity. The presence of water and.OH results in an increase in ionic conductivity of NaBi3O4Cl2 owing to diffusion of H2O into NaBi3O4Cl2, partially forming binding.OH through oxygen vacancy repairing. Ab initio calculations reveal that the electrons significantly accumulate around.OH and induce a more negative charge center, which can promote Na+ hopping. This finding is fundamental for understanding the essential role of H2O in halide‐based SEs and provides possible roles in designing water‐insensitive SEs through control of defects. [ABSTRACT FROM AUTHOR]

In hunting for safe and cost‐effective materials for post‐Li‐ion energy storage, the design and synthesis of high‐performance solid electrolytes (SEs) for all‐solid‐state batteries are bottlenecks. Many issues associated with chemical stability during processing and storage and use of the SEs in ambient conditions need to be addressed. Now, the effect of water as well as oxyhdryl group (.OH) on NaBi3O4Cl2 are investigated by evaluating ionic conductivity. The presence of water and.OH results in an increase in ionic conductivity of NaBi3O4Cl2 owing to diffusion of H2O into NaBi3O4Cl2, partially forming binding.OH through oxygen vacancy repairing. Ab initio calculations reveal that the electrons significantly accumulate around.OH and induce a more negative charge center, which can promote Na+ hopping. This finding is fundamental for understanding the essential role of H2O in halide‐based SEs and provides possible roles in designing water‐insensitive SEs through control of defects. [ABSTRACT FROM AUTHOR]