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Lattice Distortion of Current Collector upon Supporting Dimensional Changes of Electrode-Active Materials in Alkali-Metal-Ion Batteries

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journal contribution
posted on 27.05.2020, 13:34 by Dewika Mishra, Manoj K. Jangid, Sumit Chhangani, Pranay Gandharapu, M. J. N. V. Prasad, Amartya Mukhopadhyay
A current collector, which connects the electrode-active material electronically to the external circuit, is a critical component of an alkali-metal-ion battery. However, it is the least investigated component, especially toward any damage done upon supporting dimensional changes of electrode-active materials during alkali-metal-ion insertion/removal. Against this backdrop, orientation imaging microscopy, together with kernel average misorientation analysis, presents strong evidence toward the occurrence of lattice distortion/deformation, increases of local misorientation, and geometrically necessary dislocations of Cu current collector, in significant terms, upon supporting electrochemical lithiation/delithiation of Si. Creation of such lattice defects also decreases the electronic conductivity of the current collector, thus interfering with its main function. All of the above logically contribute to instability and capacity fade of the electrode. Interestingly, the presence of a graphene-based interlayer between a-Si and Cu suppresses the above damages, thus contributing to the improvement in cyclic stability by protecting not only the active material but also the current collector.