Composition controlled nickel cobalt sulfides core-shell structure as high capacity and good rate-capability electrodes for hybrid supercapacitors Lei Zhang, + Haitao Zhang, +, * Long Jin, Binbin Zhang, Fangyan Liu, Hai Su, Fengjun Chun, Qinghan Li, Jinfang Peng, Weiqing Yang * Key Laboratory of Advanced Technologies of Materials (Ministry of Education), School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu 610031, China. *To whom correspondence should be addressed. E-mail: wqyang@swjtu.edu.cn, haitaozhang@swjtu.edu.cn. [+] These authors contributed equally to this work. Electronic Supplementary Material (ESI) for RSC Advances. This journal is © The Royal Society of Chemistry 2016