【摘要】 水系混合离子电池因低成本、高安全性等优点在小型可穿戴电子产品中受到了广泛关注,但是其有限的面积能量密度阻碍了其在微型储能器件中的应用.构筑厚电极是实现高面积能量密度的一种有效策略,但电极厚度增加所带来的离子/电子传输迟缓、机械柔性差等问题,限制了传统厚电极的电化学能.基于此,本文提出3D打印策略构筑兼顾超高活性物质负载和快速离子扩散动力学的磷酸铁锂（LFP）厚电极,实现了超高面积能量密度锂±锌混合离子电池. 3D打印结构设计赋予电极规则宏观孔结构,冷冻干燥进一步在结构中引入大量的微观孔,为多级离子传输提供畅通无阻的扩散通道,保证了电极在厚度增加的情况下快速的离子扩散动力学.在该3D打印电极中,均匀分散的碳纳米管（CNTs）和纤维素纳米纤维（CNFs）形成相互连通的三维网络结构,均匀包裹住LFP活性材料,既保证了快速的电子转移,又有效地消除了循环过程中电极的内应力.得益于以上优势, 3D打印的超厚（2.08 mm）LFP/CNT/CNFs电极应用于锂±锌混合离子电池正极实现了创纪录的面积能量密度(5.25 mWh cm^-2),优于几乎所有报道的锌基混合离子、单离子电池和电容器.这项工作为开发高面积能量密度储能器件提供了新思路.更多还原

【Abstract】 The limitation of areal energy density of rechargeable aqueous hybrid batteries（RAHBs） has been a significant longstanding problem that impedes the application of RAHBs in miniaturized energy storage.Constructing thick electrodes with optimized geometrical properties is a promising strategy for achieving high areal energy density, but the sluggish ion/electron transfer and poor mechanical stability, as well as the increased electrode thickness, itself present well-known problems. In this work, a 3D printing technique is introduced to construct an ultra-thick lithium iron phosphate（LFP）/carboxylated carbon nanotube（CNT）/carboxyl terminated cellulose nanofiber（CNF） composite electrode with uncompromised reaction kinetics for high areal energy density Li–Zn RAHBs. The uniformly dispersed CNTs and CNFs form continuous interconnected 3D networks that encapsulate LFP nanoparticles, guaranteeing fast electron transfer and efficient stress relief as the electrode thickness increases. Additionally, multistage ion diffusion channels generated from the hierarchical porous structure assure accelerated ion diffusion. As a result, LFP/Zn hybrid pouch cells assembled with 3D printed electrodes deliver a well-retained reversible gravimetric capacity of about 143.5 m Ah g^-1 at 0.5 C as the electrode thickness increases from 0.52 to 1.56 mm, and establish a record-high areal energy density of 5.25 m Wh cm^-2 with an impressive utilization of active material up to 30 mg cm^-2 for an ultra-thick（2.08 mm） electrode, which outperforms almost all reported zinc-based hybrid-ion and single-ion batteries. This work opens up exciting prospects for developing high areal energy density energy storage devices using 3D printing.更多还原