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There are various component contacts in porous electrodes, such as the direct contact between the active particles and the particle–current collector, during electrode manufacturing and lithium‐ion battery electrochemical cycles. Herein, an electrochemical–mechanical representative volume element model is developed to study the contact behavior of porous electrodes. For the direct contact behavior of multiple particles, stronger battery constraints and larger size differences enhance the reduction in Li‐ion concentration in the contact area of the active particles in the porous electrode and the contact stress in the porous electrode particles. For the contact between the active particles and current collector, the decrease in the elastic modulus of the current collector slightly increases the contact radius and significantly reduces the contact stress. By comparing the contact area and contact stress of the smooth and rough current collectors, the latter has a smaller contact area and larger contact stress when in contact with active particles. These findings provide insights into designing Li‐ion batteries from the perspective of contact stress to minimize the mechanical failure of porous electrodes. [ABSTRACT FROM AUTHOR]

The extrusion of dendrites and gas bubbles can lead to the appearance of dead lithium, which seriously reduces the coulomb efficiency, hindering the rapid development of high‐energy batteries. Therefore, it is very important to study the internal mechanism of the interaction between lithium dendrites and gas bubbles during electrochemical processes. In this paper, we have designed and developed a special in situ observation device for investigating the dendrite behavior. We also modified the phase‐field model to study the growth of lithium dendrites on the electrode with bubbles. The cantilever beam theory was applied to study the interaction between lithium dendrites and gas bubbles. The observed effects comprise the coalescence of gas bubbles, changing of lithium‐ion transport path on graphite electrode surface near the gas bubble, and bending of dendrites in front of the bubble. The local variation in the lithiation speed can be attributed to the insulating properties of the gas bubbles. Phase‐field simulation results of the interaction between dendrites and gas bubbles were consistent with the experimental results. A deeper insight into the gas‐bubble behaviors during dendrite growth with the presented simulation and experiment techniques becomes possible, which could be helpful to choose an appropriate structural design for reducing bubbles and lithium dendrites. [ABSTRACT FROM AUTHOR]