Cation reordering instead of phase transitions: Origins and implications of contrasting lithiation mechanisms in 1D ζ- and 2D α-V 2 O 5

Significance The function of cathode materials is determined by factors transcending decades of length scales, spanning the range from the crystal structure and composition of the compound to the dimensions and morphologies of the particles, their connectivity with other particles and with the conductive matrix, and their spatial location relative to the electrolyte–electrode interface. Mitigating the constraints and degradation mechanisms that limit cathode materials from realizing their full potential requires careful consideration of the electrode structure spanning multiple length scales. In this work, we explore an intriguing concept: For the same exact composition (V 2 O 5 ), can the atomic connectivity be altered to stabilize a metastable polymorph that provides access to an entirely distinctive cation insertion and diffusion mechanism?