You will be shown an abstract from a biomedical research paper. Given this abstract, your task is to extract all unique entities of the following types: ["Chemical"].

Please return the output as a JSON object of the format: {"Chemical": ["Arsenic", ...]}. The keys should be entity types and values should be lists of extracted entities belonging to the corresponding type. If you cannot find entities belonging to a specific type, the value should be [].

Only output the JSON object and do not include any additional text.

Abstract:

High electrochemical performance based on ultrathin porous CuO nanobelts grown on Cu substrate as integrated electrode. A facile and low-cost approach has been developed to fabricate porous CuO nanobelts directly grown on a Cu substrate. The as-prepared CuO samples can be directly used as integrated electrodes for lithium-ion batteries and pseudo-supercapacitors without the addition of other ancillary materials such as carbon black or a binder to enhance electrode conductivity and cycling stability. The unique nanostructural features endow them with excellent electrochemical performance as demonstrated by high capacities of 640 mA h g(-1) after 100 cycles at 0.2 C rate and an excellent specific capacitance of 340 F g(-1), which corresponds to the energy density of 45 W h kg(-1). The cyclability of the electrode demonstrates only a 10-15% loss in capacitance over 5000 cycles.
{"Chemical": ["CuO", "lithium", "carbon black", "Cu"]}