In this work, FeCo-Se and NiCo-PO₄ were electrodeposited on nickel foam (NF) successively to prepare a cathode material for asymmetric supercapacitors (ASCs) and NiCo//Bi batteries. FeCo-Se@NiCo-PO₄ combines the advantages of transition metal selenides (TMSs) and transition metal phosphates (TMPs). FeCo-Se electrodeposited in the underlying layer can facilitate electron transfer for higher conductivity. NiCo-PO₄ in the outer layer can facilitate OH^– ions diffusion because TMPs can be intercalated into ions readily and the outer robust P–O bond of TMPs can stabilize the structure. Precisely because the hierarchical structure maximizes the synergy between FeCo-Se and NiCo-PO₄, FeCo-Se@NiCo-PO₄ delivers a rapid electron/ion transfer capability and superior electrochemical performance. The FeCo-Se@NiCo-PO₄ exhibits a high specific capacitance of 2221.5 F g^–1 (888.6 C g^–1) at 1 A g^–1. Its aqueous ASC shows specific capacitance of 115.8 F g^–1 at 1 A g^–1 and all-solid-state ASC presents high reversibility. Its aqueous NiCo//Bi battery has superior durability of about 60% capacity retention and 98% Coulombic efficiency after 2300 cycles. And its all-solid-state NiCo//Bi battery possesses a higher energy density and power density.

中文翻译：

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采用分层策略为超级电容器和 NiCo//Bi 电池设计的 FeCo-Se@NiCo-PO4 电极


在这项工作中，FeCo-Se 和 NiCo-PO₄ 先后电沉积在泡沫镍 （NF） 上，制备了用于不对称超级电容器 （ASCs） 和 NiCo//Bi 电池的正极材料。FeCo-Se@NiCo-PO₄ 结合了过渡金属硒化物 （TMS） 和过渡金属磷酸盐 （TMP） 的优点。电沉积在底层中的 FeCo-Se 可以促进电子转移以获得更高的电导率。外层的 NiCo-PO₄ 可以促进 OH^– 离子扩散，因为 TMP 可以很容易地嵌入离子中，并且 TMP 的外部坚固的 P-O 键可以稳定结构。正是因为分层结构最大限度地发挥了 FeCo-Se 和 NiCo-PO₄ 之间的协同作用，FeCo-Se@NiCo-PO₄ 提供了快速的电子/离子转移能力和卓越的电化学性能。FeCo-Se@NiCo-PO₄ 在 1 A ^g-1 时表现出 2221.5 F g^–1 （888.6 C g^–1） 的高比电容。其水性 ASC 在 1 A ^g-1 时显示 115.8 F ^g-1 的比电容，全固态 ASC 具有高可逆性。其水系 NiCo//Bi 电池在 2300 次循环后具有约 60% 的容量保持率和 98% 库仑效率的卓越耐用性。其全固态 NiCo//Bi 电池具有更高的能量密度和功率密度。