The combination of in-situ synchrotron X-ray diffraction and insitu stress measurements performed during electrochemical Li-alloying/dealloying of amorphous Si (a-Si) films, having ∼150 nm thick NiTi film as an interlayer between it and the current collector, has confirmed the occurrence of reversible B2↔B19′ phase transformation and associated pseudoelastic deformation of the nanoscaled NiTi film in response to dimensional changes of a-Si. The in-situ stress results also indicate that pseudoelastic deformation of the NiTi interlayer helps "buffer" the stress development in a-Si during lithiation/ delithiation. Top-view and cross-section imaging at different stages of electrochemical cycling confirm the concomitant improvement in integrity of a-Si film electrode over multiple lithiation/delithiation cycles, in the presence of the NiTi interlayer. This, in turn, contributes toward significant improvement in the cyclic stability of a-Si. In more specific terms, the presence of NiTi interlayer improved the capacity retention of a-Si to ∼78% after 50 cycles, as compared to just ∼10% retention in the absence of any buffer interlayer. This is expected to allow moving ahead from the usually investigated material as a buffer interlayer, viz., graphenic carbon; as also confirmed by our comparative studies. However, the synchrotron X-ray diffraction results also indicate the presence of some retained B19′ phase in the NiTi interlayer after each lithiation−delithiation "full" cycle, presumably due to straining of the NiTi interlayer beyond the 8−10% limit for pseudoelasticity. This reduces the effectiveness of the interlayer with cycling, as also evidenced with the in-situ stress results. Hence, sustaining the effectiveness of the NiTi interlayer over multiple cycles necessitates addressing this issue via careful designing/engineering of the electrode and/or the electrochemical cycling parameters.