In situ formation of MnO@N-doped carbon for asymmetric supercapacitor with enhanced cycling performance

Searching electrodes with high specific capacitance, rate capability, long cycling life and economic efficiency is central for next-generation supercapacitors. In this work, a hybrid electrode consisting of MnO and N-doped carbon (MnO-NC) was constructed using KMnO4 and carboxymethyl chitosan as manganese sources and carbon sources respectively. The effect of the ratio of KMnO4 to carboxymethyl chitosan on the structure and electrochemical performance of MnO-NC was investigated in detail. At the optimized condition, a high specific capacitance of 326.36 F g(-1) was obtained with satisfied cyclic stability. Moreover, an asymmetric supercapacitor (ASC) device (MnO-NC//AC), consisting of MnO-NC as the positive electrode and activated carbon (AC) as the negative electrode was assemble, which exhibited a specific energy density was 9.35 W h kg(-1) at a power density of 374.83 W kg(-1). Owing to the long activation process, the capacitance of the ASC device remains 172% after 10 000 cycles. These results indicate that the prepared MnO-NC has great prospects for the application of high-performance supercapacitors.