2.4.3 循环稳定性循环稳定性是考察电极性能好坏的一个重要因素，图1

2.4.3 cycle stability <br>loop stability is an important quality of the factors influencing the performance of the electrode, and FIG. 10 is a MnO2 MnO2 / PPy life cycle curve 1A in cycle time 1000 rings • 1 g-. Before the loop coil 200, the specific capacity of the electrode tends to increase then began to decline, because the initial cycle ionic electrolyte material in contact with the active material is insufficient, fails to reach the phase, desorption occurs first surface; with time extension, the oxidation-reduction reaction in the bulk begins to store charge, has presented an increasing trend [28]. Reduction in capacity and in part because of falling or dissolved unstable than the active material particles caused. After 1000 cycles the charge and discharge, and MnO2 MnO2 / PPy electrode specific capacity losses were 13.5% and 5.9%, to improve the cycle performance of MnO2 PPy / PPy and thanks to the synergy of MnO2 and porous composite material. In the long-term charge-discharge process, to provide a stable MnO2 chain PPy a solid support, to improve its poor cycle stability defects; and the conductive properties of PPy and make up the shortcomings of poor conductivity MnO2, interaction between the two, so as to effectively increased MnO2 / PPy composite electrode cycle life [29-30]. Porous composite electrode material MnO2 / PPy, such that it has a high specific surface area, provides more active sites, was favorable to the electrolyte ions and electrons, thereby increasing the specific capacity.

2.4.3 Cycle stability<br>Cycle stability is an important factor to investigate the performance of the electrode, Figure 10 is MnO2 and MnO2/PPy cycle 1000 cycle curve at 1A-g-1. Before the cycle 200 turns, the electrode ratio increases and then begins to decline, because the ions in the electrolyte in the early cycle do not have sufficient contact with the active material material, failed to reach the body phase, the first surface suction attachment occurs; Part of the decline in capacity is due to the loss or dissolution of unstable particles of the active substance. After 1000 turns of charge and discharge, MnO2 and MnO2/PPy electrode ratio slosses of 13.5% and 5.9% respectively, MnO2/PPy cycle performance is due to the synergy of MnO2 and PPy and the porousness of composite materials. In the long-term charging and discharge process, MnO2 provides a solid support for the stability of the PPy chain, improving the defect of poor circulation stability, while the conductive properties of PPy compensate for the disadvantages of poor conductivity of MnO2, which interacts effectively, thus effectively improving the cycle life of MnO2/PPy composite electrodes. The porousnature of MnO2/PPy composite electrode material makes it have a higher surface area, which can provide more active sites, which is conducive to the transfer of electrolyte ions and electrons, thus improving the ratio capacity.

2.4.3 cycle stability<br>The cycle stability is an important factor to evaluate the performance of the electrode. Figure 10 shows the cycle life curve of MnO2 and MnO2 / PPy at 1a · g-1 for 1000 cycles. Before 200 cycles, the specific capacity of the electrode tends to increase, and then it begins to decrease, because the ions in the electrolyte at the beginning of the cycle do not contact the active material sufficiently and fail to reach the bulk phase, so the surface adsorption and desorption occurs first; with the extension of time, the redox reaction in the bulk phase begins to store the charge, so it shows an increasing trend [28]. The decrease of specific capacity is also partly due to the shedding or dissolution of unstable active substance particles. After 1000 cycles of charging and discharging, the specific capacity of MnO2 and MnO2 / PPy electrodes lost 13.5% and 5.9% respectively. The improvement of MnO2 / PPy cycle performance is attributed to the synergistic effect of MnO2 and PPy and the porosity of composite materials. In the long-term charging and discharging process, MnO2 provides a solid support for the stability of PPy chain and improves the defects of poor cycle stability; the conductivity of PPy makes up for the disadvantages of poor conductivity of MnO2, and the interaction between them effectively improves the cycle life of MnO2 / PPy composite electrode [29-30]. MnO2 / PPy composite electrode material has higher specific surface area and more active sites, which is conducive to the transfer of ions and electrons in the electrolyte, thus improving the specific capacity.<br>