The increasing power demand for flexible electronics stimulates the development of flexible batteries with high performance, light weight, and low cost. However, the fabrication of flexible cathodes for sodium-ion batteries is still a great challenge. In this work, freestanding three-dimensional P2/P3 heterostructured Na_0.7CoO₂ nanosheet arrays are grown on carbon cloth via a “solvothermal sodiation” reaction followed by calcination in argon atmosphere. The P2 and P3 phases have coherent interface perpendicular to the [00ℓ] direction in the P2/P3–Na_0.7CoO₂ nanosheets, which effectively suppresses the interlayer variation during charge/discharge, resulting in smaller volume change and improved structure stability with repeated Na⁺ intercalation/deintercalation. The self-standing P2/P3–Na_0.7CoO₂ nanosheet array electrode exhibits high specific capacity (126.2 mAh g⁻¹ at 0.1 C and 85.5 mAh g⁻¹ at 10 C) and superior cycle performance (92.4% after 300 cycles at 1 C). By coupling with hard carbon (HC) coated carbon cloth as anode, a P2/P3–Na_0.7CoO₂//HC flexible sodium-ion battery device is successfully constructed, delivering large reversible capacity of 120.5 mAh g⁻¹ at 0.1 C (based on the weight of cathode material). The present fabrication of the three-dimensional flexible P2/P3–Na_0.7CoO₂ cathode provides new opportunity for the construction of advanced flexible sodium-ion batteries.

对柔性电子设备的不断增长的电力需求刺激了高性能，轻量化和低成本的柔性电池的发展。然而，用于钠离子电池的柔性阴极的制造仍然是巨大的挑战。在这项工作中，独立的三维P2 / P3异质结构Na _0.7 CoO ₂纳米片阵列在碳布上通过“溶剂热加成”反应生长，然后在氩气中煅烧。在P2 / P3-Na _0.7 CoO ₂纳米片中，P2和P3相具有垂直于[00ℓ]方向的相干界面，可有效抑制充/放电过程中的层间变化，从而减小体积变化并改善结构稳定性（重复Na⁺插层/反插层。自立式P2 / P3-Na _0.7 CoO ₂纳米片阵列电极具有高比容量（0.1 C下为126.2 mAh g ^-1和10 C下为85.5 mAh g ^-1）和优异的循环性能（1次300次循环后为92.4％） C）。通过与涂有硬质碳（HC）的碳布作为阳极结合，成功构建了P2 / P3-Na _0.7 CoO ₂ // HC柔性钠离子电池装置，在0.1 C时可提供120.5 mAh g ^-1的大可逆容量（基于正极材料的重量）。三维柔性P2 / P3-Na _0.7 CoO _2的制备 阴极为先进的柔性钠离子电池的建造提供了新的机会。