Part of LTO's open-circuit voltage.
The energy values $ε_{8a}$, $ε_{16c}$, and $J$, defined and calculated as described in Energetic model of Lithium intercalated in LTO lattice, have three important properties:
It intuitively follows from this that to minimise the potential energy, in $\mathrm{LiTi_{2}O_4}$ (0% stoichiometry), almost all Lithium ions stay at 8a sites; in $\mathrm{Li_2Ti_2O_4}$ (100% stoichiometry), almost all Lithium ions stay at 16c sites (any shift from a 16c to an 8a site means three new interactions with neighbouring ions at 16c, so the energy balance of such shift, $3J - \Deltaε$, is negative); in $\mathrm{Li_xTi_2O_4}$ where x is between 1 and 2 (stoichiometry between 0% and 100%), the system "prefers" to maintain mostly homogeneous areas of a particle with 8a and 16c sites occupied to minimise the overall number of neighbouring Lithium ions at 8a and 16c sites.
As the stoichiometry rises from 0% to 100%, the areas of the particle bulk (or a single area, e. g. the surface of a particle) where 16c sites are occupied become progressively larger, and the areas (or a single area, e. g. the interior of a particle) where 8a sites are occupied become progressively smaller. During this whole phase transition, the open-circuit voltage of a particle stays at $2ε_{16c} - ε_{8a} = ε_{8a} + 2\Deltaε$. This page explains this arithmetic in the case of phase transitions from Stage I ($\mathrm{LiC_{6}}$) to Stage II ($\mathrm{LiC_{12}}$) of graphite which has a 2:1 proportion between stage populations as well LTO with its 8a and 16c sites.