化学改性MnO2的制备及可充性

制备可充锌锰电池的关键技术之一是提高MnO2的可逆性。采用化学沉淀氧化法制备改性MnO2。研究了锰盐、掺杂物质、氧化剂、温度等对MnO2可逆性的影响。采用模拟电池及微电极技术研究MnO2的充放电性能，结合XRD、SEM检测改性MnO2的晶形和形貌。实验结果表明，当以Bi（NO3）3为掺杂物质时，制备改性MnO2的优化工艺条件是：n（Mn）／n（Bi）（摩尔比）为6～10，氧化剂用NaClO，锰盐可用Mn（NO3）2或MnSO4，25 ℃，反应时间10～15 h。所得改性MnO2呈疏松微晶粒状，是以β-MnOOH为主的β-MnOOH与β-BiOOH的混合晶相。该样品经第10次循环充放电后，其放电容量为初始放电容量的121％，10次累积放电容量是电解MnO2（EMD）的3倍。表明掺Bi3＋对改善MnO2的可逆性和提高放电容量有重要作用。

Preparation and rechargeability of chemical modified manganese dioxide

Enhancing the invertibility of MnO2 was one of key technologies of preparing chargeable Zn-MnO2 battery． Chemical deposition oxidation was adopted to prepare modified MnO2 and manganic compounds， adulterants， oxidants， humidity effected to invertibility of MnO2 were studied． Charge and discharge capability of MnO2 was studied by adopting simulation cell and microelectrode． Crystal and shape of modified MnO2 were detected by XRD and SEM． The results show that the optimal technological conditions for preparing modified MnO2 by using Bi（NO3）3 as adulterant is as following： mole ratio of n（Mn）／n（Bi） is 6～10， oxidant is NaClO， manganic compound is Mn（NO3）3 or MnSO4， temperature is 25 ℃， reaction time is 10～15 h． The modified MnO2 is loosen micro-crystal powder， which is mixture of β-MnOOH with a little β-BiOOH． The powders discharge capability is 121％ of initial discharge capability after the tenth charge and discharge cycle． The cumulate discharge capability of the tenth charge and discharge cycle is triple electrolyze MnO2 （EMD）． These show that it is important addition Bi3＋ to improve invertibility and to enhance discharge capability of MnO2．