Calcium-ion batteries (CIBs) have emerged as a promising alternative for electrochemical energy storage. The lack of high-performance cathode materials severely limits the development of CIBs. Vanadium oxides are particularly attractive as cathode materials for CIBs, and preinsertion chemistry is often used to improve their calcium storage performance. However, the room temperature cycling lifespan of vanadium oxides in organic electrolytes still falls short of 1000 cycles. Here, based on preinsertion chemistry, the cycling life of vanadium oxides is further improved by integrated electrode and electrolyte engineering. Utilizing a tailored Ca electrolyte, the constructed freestanding (NH₄)₂V₆O₁₆·1.35H₂O@graphene oxide@carbon nanotube (NHVO-H@GO@CNT) composite cathode achieves a 305 mAh g⁻¹ high capacity and 10 000 cycles record-long life. Additionally, for the first time, a Ca-ion hybrid capacitor full cell is assembled and delivers a capacity of 62.8 mAh g⁻¹. The calcium storage mechanism of NHVO-H@GO@CNT based on a two-phase reaction and the exchange of NH₄⁺ and Ca²⁺ during cycling are revealed. The lattice self-regulation of V─O layers is observed and the layered vanadium oxides with Ca²⁺ pillars formed by ion exchange exhibit higher capacity. This work provides novel strategies to enhance the calcium storage performance of vanadium oxides via integrated structural design of electrodes and electrolyte modification.

中文翻译：

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用于长效钙离子电池的具有晶格自调节和离子交换功能的独立式钒酸铵复合阴极

钙离子电池（CIB）已成为电化学储能的一种有前途的替代品。高性能正极材料的缺乏严重限制了CIB的发展。钒氧化物作为 CIB 的阴极材料特别有吸引力，并且预插入化学通常用于提高其钙存储性能。然而，有机电解液中钒氧化物的室温循环寿命仍低于1000次循环。在此，基于预插入化学，通过集成电极和电解质工程进一步提高了钒氧化物的循环寿命。利用定制的Ca电解质，构建的独立式(NH ₄ ) ₂ V ₆ O ₁₆ ·1.35H ₂ O@氧化石墨烯@碳纳米管(NHVO-H@GO@CNT)复合正极实现了305 mAh g ^-1高容量和10 000 次循环，创纪录的长寿命。此外，首次组装了钙离子混合电容器全电池，容量达到62.8 mAh g ^-1。揭示了NHVO-H@GO@CNT基于两相反应以及循环过程中NH ₄ ⁺和Ca ²⁺交换的钙储存机制。观察到V─O层的晶格自调节，离子交换形成的带有Ca ²⁺柱的层状钒氧化物表现出更高的容量。这项工作提供了通过电极和电解质改性的集成结构设计来增强钒氧化物的钙存储性能的新策略。