where the ε is the overall porosity of the porous electrode, D 0 is the diffusivity of electrolytes and D eff is the effective diffusivity of the ions through the whole porous electrode. In general, an elevated level of tortuosity results in increased ion transport resistance, thereby negatively affecting the performance of the battery. Conversely, a lower degree of tortuosity promotes faster ion transport, which enhances the battery's overall performance and enhances its efficiency.