This can be further illustrated by the comparison of the specific capacitances of Ni-Mn LDH, Co-Mn LDH and NiCoMn LDH in Fig. S4 [17]. The specific capacitance of Ni-Mn LDH is the highest, which can be assigned to highly active Ni2+
On the other hand, during the synthesis process, GO could oxidize some metal ions in the solution. Co2+and Mn2+
could be readily oxidized to be trivalent ions, but Ni2+ is more stable than them. It is reasonable to believe that partial Co ions in Co-Mn LDH/rGO are Co3+ thus leading to a low specific capacitance. Then Ni-Mn LDH/rGO has a higher
capacitance than Co-Mn LDH/rGO. Meanwhile, we can see that both Ni-Mn LDH/rGO and Co-Mn LDH/rGO hybrids show higher specific capacitances than the pure LDH counterparts (1635 and290 F g1) at 1 A g1 Here, the contribution from rGO is well
presented by improving the specific capacitance. The specific
capacitances of the four samples are displayed in Table S1 in
supplementary information. The capacitance of Ni-Mn LDH/rGO
at 10 A g
1
can still be 71% of that at 1 A g
1
, but only 68% for NiMn LDH, indicating the better rate capability of Ni-Mn LDH/rGO
composite. In addition to improving the specific capacitance and
rate capability, the influence of rGO can be further understood by
the following cycling tests and EIS analyses