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Laser shock peening can potentially enhance fatigue life of titanium components by inducing compressive residual stresses in surface layers much deeper than caused by traditional shot peening (SP). In the present study, the high cycle fatigue (HCF) performance of α Ti-alloy Ti-2.5Cu, (α + β) Ti-alloy TIMETAL 54M and the metastable β Ti-alloy TIMETAL LCB was investigated after laser shock peening without coating (LPwC). The fatigue results were interpreted by examining the changes of surface morphology, microhardness and residual stress generated in the surface layer. Furthermore, thermal stability of residual stresses in aged Ti-2.5Cu, as an example, was evaluated after annealing LPwC-treated material at various elevated temperatures and exposure times by applying a Zener-Wert-Avrami-approach. The depth profiles of residual stresses were obtained by means of synchrotron X-ray diffraction or by incremental hole drilling method. Results revealed that the HCF performance of Ti-2.5Cu and TIMETAL LCB was markedly improved after LPwC, while it was deteriorated in TIMETAL 54M. Compared to LPwC, better 10 7 fatigue strength of Ti-2.5Cu was obtained after ball-burnishing (BB). Moreover, LPwC-induced residual stresses are thermally more stable than shot peening-induced ones.

New high‐capacity intercalation cathodes of Li2VxCr1−xO2F with a stable disordered rock salt host framework allow a high operating voltage up to 3.5 V, good rate performance (960 Wh kg−1 at ≈1 C), and cycling stability.

Li-ion batteries have driven the technological evolution of portable electronics, automotive, and stationarya pplications over the past decades.[1] However, the poor low-temperature performance of Li-ion batteries impedes their specific applications, such as fora erospace, defense, and transportation systems.[2] When operating at reduced temperatures, especially below 0 8C, the kinetic performance of the employed materials, governed by the intrinsic transport property for electrons and Li ions, becomes ac ritical factor determining the deliverable capacity.[3] Classic Li-ion battery cathode materials suffer from substantial capacity loss, [4] severe voltage hysteresis, [5] and change in voltage profiles.[6] As reported, from 25 to 0 8C, ac ommercialL iFePO 4 -based cell has ac apacity retention of only 42 %. [7] The sluggish kinetics of Li + transport and the reduced electronic conductivity in the solid LiFePO 4 phase at low temperatures leads to the voltage profiles evolving from ap lateau-like to sloping regime.[8] For layered Ni-Mn-Co oxides, [9] ad ischarge voltage downshift of 0.5 Vh as been observed when reducing the temperature from 25 to À20 8C. [6] In addition, the performance deteriorationo fa node materials and the appliede lectrolytes at low temperatures contributet ot he poor overall battery performance. [2,10] At sub-ambient temperatures, Li platingt ends to occur at the graphite anode,o wing to the reduced Li + intercalation into graphite.[11] At temperatures below À10 8C, the ionic mobility in the electrolyte solution and conductivity of the conventional binary carbonate electrolyte fall rapidly.[12] The optimization of the electrolyte formulations for different electrode materials at low temperatures still remains to be solved. Nevertheless, exploring new cathodem aterials with well-retaineds pecific energiesa tr educed temperatures is am ore decisive step towards broad applications of Li-ion batteries.We have recentlyr eportedt hat an ew cathode material, Li 2 VO 2 F, with ad isordered rock-salt structure can deliver ah igh initial intercalation capacity when cycling at al ow current rate.[13] However,L i 2 VO 2 Fs uffers from capacity fading whilst cycling. It has been found that the poor cycling performance of Li 2 VO 2 Fc an be improved by substituting Cr forVi nt his system.[14] Moreover,t he cyclability of the mixed V/Cr oxyfluorides depends on the applied chargecutoff voltages and operation temperature. Af acile Li + chemical diffusion in such ac lass of materials favors the kinetic properties.[15] Herein,w ee xplore the composition-dependent, low-temperature properties of the oxyfluorides and examine the structural features responsible for the cycling performance.The low-temperature rate capabilities of Li 2 VO 2 F, Li 2 CrO 2 F, and Li 2 Cr 0.2 V 0.8 O 2 Fw ere first evaluated at À10 8Ca tv arious current densities from 26 to 1050 mA g À1 ,a nd then back again at 26 mA g À1 (Figures 1a-c

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