1.3.4 电化学性能研究采用三电极体系，即上述制备的电极为工作电极，

Electrochemical Properties 1.3.4 <br>using three-electrode system, i.e., the electrode prepared above as a working electrode, a platinum wire electrode as the counter electrode, a saturated calomel electrode (SCE) as the reference electrode, in a 0.5 mol L-1 Na2SO4 electrolyte the electrochemical properties of a series of tests, all tests were performed at room temperature. Specific capacity of MnO2 / PPy composite electrode material obtained charge - discharge curve according to the calculated discharge curve, as shown in equation (1):

1.3.4 Electrochemical Performance Research<br>Using a three-electrode system, i.e. the above-prepared electrode is a working electrode, the platinum wire electrode is a pair electrode, saturated glycomercury electrode (SCE) is a reference electrode, a series of electrochemical performance tests are carried out in 0.5 mol L-1 Na2SO4 electrolyte, all of which are carried out at room temperature. The ratio capacity of the MnO2/PPy composite electrode material is calculated according to the discharge curve of the constant current charge and discharge curve, as shown in equation (1):

1.3.4 electrochemical performance study<br>A series of electrochemical performance tests were carried out in 0.5 mol L-1 Na2SO4 electrolyte, using the three electrode system, i.e. the electrode prepared above as the working electrode, the platinum wire electrode as the counter electrode and the saturated calomel electrode (SCE) as the reference electrode. The specific capacity of MnO2 / PPy composite electrode material is calculated according to the discharge curve of constant current charge discharge curve, as shown in formula (1):<br>