Layered metal oxides have been widely used as the best cathode materials for commercial lithium-ion batteries and are being intensively explored for sodium-ion batteries. However, their application to potassium-ion batteries (PIBs) is hampered because of the poor cycling stability and low rate capability due to the larger ionic size of K⁺ than of Li⁺ or Na⁺. Herein, a facile self-templated strategy was used to synthesize unique P2-type K_0.6CoO₂ microspheres that consist of aggregated primary nanoplates as PIB cathodes. The unique K_0.6CoO₂ microspheres with aggregated structure significantly enhanced the kinetics of the K⁺ intercalation/deintercation and also minimized the parasitic reactions between the electrolyte and K_0.6CoO₂. The P2-K_0.6CoO₂ microspheres demonstrated a high reversible capacity of 82 mAh g^–1 at 10 mA g^–1, high rate capability of 65 mAh g^–1 at 100 mA g^–1, and long cycle life (87% capacity retention over 300 cycles). The high reversibility of the P2-K_0.6CoO₂ full cell paired with a hard carbon anode further demonstrated the feasibility of PIBs. This work not only successfully demonstrates exceptional performance of P2-type K_0.6CoO₂ cathodes and microspheres K_0.6CoO₂∥hard carbon full cells, but also provides new insights into the exploration of other layered metal oxides for PIBs.

中文翻译：

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用于高可逆钾离子电池的P2型K _0.6 CoO ₂微球的自模板形成

层状金属氧化物已被广泛用作商业锂离子电池的最佳阴极材料，并且正被钠离子电池广泛研究。但是，由于K ^+的离子尺寸大于Li ⁺或Na ^+的离子尺寸，其循环稳定性差和低倍率性能，阻碍了它们在钾离子电池（PIB）中的应用。在本文中，一种简便的自我模板化策略用于合成独特的P2型K _0.6 CoO ₂微球，该微球由聚集的一级纳米板作为PIB阴极组成。具有聚集结构的独特K _0.6 CoO ₂微球显着增强了K ⁺的动力学嵌入/脱嵌，并使电解质和K _0.6 CoO ₂之间的寄生反应最小化。P2-K _0.6 CoO ₂微球在10 mA g ^–1时具有82 mAh g ^–1的高可逆容量，在100 mA g ^–1时具有65 mAh g ^–1的高倍率容量，并且循环寿命长（容量为87％保留超过300个周期）。P2-K _0.6 CoO ₂全电池与硬碳阳极配对的高可逆性进一步证明了PIB的可行性。这项工作不仅成功地证明了P2型K _0.6 CoO _2的出色性能阴极和微球体ķ _0.6的CoO ₂ ∥hard碳全电池，而且还提供了新的见解为的PIB其它层状金属氧化物的探索。