Dynamically Stable Networks for Ion Transport in Lithium Transition-Metal Phosphates.

Crystalline ionic electrodes provide long-range ordered paths for ion transport, yet they are prone to progressive atomic distortion, especially in Li-transition-metal-embedded systems. This inherent dynamic distortion creates a paradox between maintaining long-range-ordered ion transport pathways and achieving long-term electrochemical applicability. Here, inspired by the dynamic invariance of percolation networks, we introduce amorphous lithium transition-metal phosphates featuring a dynamically stable ion-transport network (DSITN) composed of branched Li+-percolation channels. The DSITN enables isotropic long-range Li+ migration in amorphous solids and dynamically preserves percolation pathways against structural distortion during charge-discharge cycling. For example, LiCoPO4, a canonical electrode whose Li+-transport pathways usually degrade within 30 charge/discharge cycles in the crystalline state, maintains electrochemical stability over 700 cycles when rendered amorphous with DSITNs. DSITNs were also constructed in amorphous phases of other representative materials (e.g., LiFePO4 and LiMn0.5Fe0.5PO4) with robust Li+ migration pathways even under fully random cation antisites, confirming their general validity. This achievement establishes an alternative design strategy for coupling ionic mobility with structural resilience against progressive atomic distortion in high-performance ionic electrodes.