【摘要】 针对无钴锰基富锂材料Li_1.2Ni_0.2Mn_0.6O₂固有的循环稳定性差、循环电压衰减严重等问题,研究了铝掺杂结合固相煅烧法对该材料在微观形貌及结构、电化学性能等方面的影响。研究结果显示,铝掺杂不仅能促使该材料的表层形貌更加致密,而且可以为该材料带来更稳定的晶体结构,这有利于该材料在长充放电循环中抵抗因结构降级带来的一系列不利因素,最终致使其电化学性能更加优异。此外,当铝掺杂量为1%（物质的量分数）时该材料在高倍率下的放电比容量、循环稳定性、电压保持率等均达到最优效果,在2.0～4.8 V电压区间内0.1C倍率下首圈放电比容量高达248.8 mA·h/g,200圈循环充放电后其放电比容量保持率由未掺杂时的57.9%提升至77.6%,循环电压保持率也由84.2%提升至85.6%。以上结果充分显示了1%铝掺杂对锰基富锂材料Li_1.2Ni_0.2Mn_0.6O₂具有优异的改良效果。更多还原

【Abstract】 In order to solve the inherent problems of poor cycling stability and serious cycling voltage attenuation of cobaltfree Mn-based lithium-rich materials of Li_1.2Ni_0.2Mn_0.6O₂,the effect of aluminum doping combined with solid phase calcination method on the micromorphology,structure and electrochemical properties of the material were studied in this paper.The results showed that the aluminum doping not only made the surface morphology of the material denser,but also brought a more stable crystal structure to the material,which was conducive to the resistance of the material to a series of adverse factors caused by the structural reversion in the long charge-discharge cycle,and finally led to its more excellent electrochemical performance.In addition,when the doping amount of aluminum was 1%,the discharge specific capacity,cycle stability and voltage retention of the material at high rate all achieved the best optimization performance.The discharge specific capacity of the first cycle at 0.1 C ratio was as high as 248.8 mA·h/g in the voltage range of 2.0～4.8 V.After 200 cycles of charging and discharging,the discharge specific capacity retention rate increased from 57.9% to 77.6%,and the cycle voltage retention rate also increased from 84.2% to 85.6%.The above results fully showed that 1% aluminum doping had excellent improvement effect on Mn-based lithium-rich materials of Li_1.2Ni_0.2Mn_0.6O₂.更多还原