Wen-Long Huang

Dissolution and free diffusion of polysulfides in ether‐based electrolyte during cycling causes fast capacity decay and low columbic efficiency in lithium‐sulfur batteries. In this work, poly(2‐ethyl‐2‐oxazoline) (PEtOx), as an additive of sulfur cathodes, can gelatinate the electrolyte in the presence of polysulfide species, which can anchor the uncontrollable diffusion of polysulfides during the discharge process. Additionally, pore structures can form in the sulfur cathode after the dissolution of PEtOx into the electrolyte. As a result, the sulfur converted from polysulfides during subsequent charging processes will deposit more uniformly in the porous cathode. This “dissolution‐redeposition” mechanism effectively reduces the loss of active materials, providing beneficial guidance for practical Li−S batteries.

The fatigue growth behaviour for surface crack in welded joints under combined tension and bending stresses is studied by fatigue crack growth tests of 16MnR steel in bow specimens. In this present paper the Newman-Raju empirical equation was used for the stress intensity factor of a surface crack. The experimental results show that the Paris’ relationship between crack growth rate and stress intensity factor range under tension and bending fatigue stresses is still valid, and the relationship between the Paris’ coefficients Ca and Cc can be represented as Cc = (0.89)m Ca .