Carbon coating with different carbon sources on rare earth hydrogen storage alloy

The rare earth hydrogen storage alloy was coated with the same contents of carbon particles using sucrose, glucose, pitch, and chitosan as carbon sources, and compared with the samples of uncoated and mechanically mixed with the carbon powder. The results show that the maximum discharge capacity (Cmax), high-rate dischargeabilitiy (HRD), and cyclic stability after 500 cycles (S500) are improved to various degrees by carbon coating. It is found that the better the fluidity of carbon source in the carbonization process, the more uniform the carbon distributed on the alloy surface, and the longer the cyclic life of the alloy electrode. The less impurity remained after carbonization and the higher degree of graphitization of carbon, the better the electrocatalytic activity and HRD performance of the alloy electrode. The alloy coated with carbon particles using sucrose as carbon source has the best electrochemical properties. Compared with the uncoated sample, the Cmax of the alloy electrode increases from 354.5 to 359.0 mAh/g, the HRD1200 increases from 65.84% to 74.39%, and the S500 increases from 63.14% to 69.63%.