**Appendix B**

Equations in terms of the averaged Li content in the crystallites *cLi* would also be useful, especially when comparing to measurements on single crystals described elsewhere [16–18]. Equations (2)–(5) in terms of *cLi* are:

$$
\langle \mathfrak{c}\_{\rm Li} \rangle = (-7.6453 V\_{\rm cell} + 2482.2171) mol \text{ } \% \pm 0.5 \text{ mol } \% \tag{A1}
$$

$$\begin{aligned} \langle \langle \mathbf{c}\_{Li} \rangle\_{\rm L} &= \left( -259.0674 \ast \left( \frac{\Gamma\_{\rm L}}{2\mathbf{x}\_{\rm c}} \right) + 56.8135 \right) mol \,\%\,\pm \,\mathbf{0}.4 \,\, mol \,\% \\ \langle \mathbf{c}\_{Li} \rangle\_{\rm G} &= \left( -588.2353 \ast \left( \frac{\Gamma\_{\rm G}}{2\mathbf{x}\_{\rm c}} \right) + 58.0412 \right) mol \,\%\,\pm \,\mathbf{0}.5 \,\, mol \,\% \end{aligned} \tag{A2}$$

$$
\langle c\_{Li} \rangle = \left( -3.9602 \ast E\_{\mathcal{S}} + 65.5987 \right) \text{mol } \% \pm 0.4 \text{ mol } \% \tag{A3}
$$

$$
\langle \mathcal{c}\_{Li} \rangle = (0.0519 \ast T\_{\mathcal{c}} - 11.3805) \,\text{mol} \,\,\% \,\,\pm 0.4 \,\,\text{mol} \,\,\% \tag{A4}
$$
