Lin Jia, Zeng Chenghui, Lin Xiaoming, Xu Chao, Su Cheng-Yong
Key Laboratory of Theoretical Chemistry of Environment, Ministry of Education, Guangzhou Key Laboratory of Materials for Energy Conversion and Storage, School of Chemistry South China Normal University Guangzhou 510006 P. R. China.
College of Chemistry and Chemical Engineering, Key Laboratory of Functional Small Organic Molecule, Ministry of Education and Jiangxi's Key Laboratory of Green Chemistry Jiangxi Normal University Nanchang 330022 P. R. China.
Adv Sci (Weinh). 2020 May 29;7(14):2000736. doi: 10.1002/advs.202000736. eCollection 2020 Jul.
Conspicuously, metal-organic frameworks (MOFs) serve as homogenously and periodically atom-dispersed self-sacrificial template for in situ engineering of hierarchical porous carbon-encapsulated micro/nanoheterostructure materials, integrating the merits of micro/nanostructure to high-volumetric energy storage. Copper phosphide represents a promising candidate due to its compact material density compared to commercial graphite. Herein, micro/nanostructured CuP/Cu encapsulated by carbon-nanotube-assembled hierarchical octahedral carbonaceous matrix (CuP/Cu@CNHO) is constructed by an in situ MOF-derived engineering for novel anode material in LIBs, which achieves an extraordinary cycling stability (a well-maintained gravimetric/volumetric capacity of 463.2 mAh g/1878.4 mAh cm at 1 A g up to 1600 cycles) and distinguished rate capability (an ameliorated capacity of 317.7 mAh g even at 10 A g), together with unprecedented heat-resistant capability (an elevated temperature of 50 °C for 1000 cycles maintaining 434.7 mAh g at 0.5 A g). The superior electrochemical performance of CuP/Cu@CNHO is credited to the large specific surface area, conductive carbon matrix and metallic copper dopants, synergistic effects of the intrinsic CuP/Cu heterostructure, and well-defined micro/nanostructure, facilitating a boosted electrochemical conductivity and accelerated diffusion kinetics.
值得注意的是，金属有机框架（MOF）作为均匀且周期性原子分散的自牺牲模板，用于原位构建分级多孔碳包覆的微/纳米异质结构材料，将微/纳米结构的优点整合到高体积能量存储中。与商用石墨相比，磷化铜因其紧凑的材料密度而成为有前景的候选材料。在此，通过原位MOF衍生工程构建了由碳纳米管组装的分级八面体碳质基质包覆的微/纳米结构CuP/Cu（CuP/Cu@CNHO）作为锂离子电池新型负极材料，其实现了非凡的循环稳定性（在1 A g下1600次循环时，保持良好的重量/体积容量分别为463.2 mAh g/1878.4 mAh cm）和卓越的倍率性能（即使在10 A g时容量仍提高到317.7 mAh g），以及前所未有的耐热能力（在50°C下1000次循环，在0.5 A g时保持434.7 mAh g）。CuP/Cu@CNHO优异的电化学性能归因于其大比表面积、导电碳基质和金属铜掺杂剂、固有CuP/Cu异质结构的协同效应以及明确的微/纳米结构，促进了电化学导电性的提高和扩散动力学的加速。
