Coherent twins for manufacturing thick lithium-rich battery positive electrodes

Thick electrodes are a key strategy for enhancing the energy density of non-aqueous lithium-based batteries. However, their practical application is hindered by sluggish ion transport, reaction inhomogeneity and mechanical degradation. Lithium-rich layered oxides offer a high theoretical specific capacity via anionic charge compensation, yet, from a practical perspective, they suffer from nanoscopic structural stress, oxygen redox irreversibility and electrode-scale transport limitations. These factors detrimentally affect performance, exacerbating degradation processes, especially in cells with thick electrodes. Here, by regulating the crystal growth process, we introduce coherent twin boundaries (CTBs) into lithium-rich layered oxides to construct quasi-three-dimensional ion diffusion pathways that accelerate Li-ion transport at the nanoscale, beyond conventional two-dimensional-layered channels, and mitigate reaction inhomogeneity. CTBs redistribute lattice mechanical stress, transforming localized strain into a more uniform configuration to enhance structural stability. CTBs also activate lattice oxygen within the LiTMO₂ (TM indicating a transition metal) domain, contributing additional reversible capacity. As a demonstration, CTBs enable battery operation across a broad temperature range from 55 °C to -15 °C, and the designed 1.05 Ah lithium-ion pouch cell achieves a specific discharge capacity retention of 88.5% after 100 cycles at 100 mA g^-1 and 30 °C with a positive electrode mass loading of 33.6 mg cm^-2.