采用高温固相反应法合成具有良好层状结构的LiNi0 .8-xAlxCo0 .2 O2 .研究发现 ,LiNi0 .71Al0 .0 9Co0 .2 O2 材料经 2 0次循环充放电后 ,其放电容量仍达 15 2mAh/ g ,是首次放电容量的97.4 % .通过XRD结构测量、慢扫描循环伏安测试和电极经多次循环后其交流阻抗测试的对比 ,表明对LiNiO2 进行Al和Co共掺杂 ,增强了材料层状结构的稳定性 ,有效地抑制了Li+嵌入脱出过程中材料的相转变 ,其充放电性能、耐过充性和循环性能都得到明显改善 .热分析测试表明 ,在高脱锂状态下共掺杂材料的热稳定性也有所提高 .
张军
,
金忠
,
杨清河
,
宋庆梅
,
马晓华
,
宗祥福
. LiNi_(0.8-x)Al_xCo_(0.2)O_2制备与电极性能的研究[J]. 电化学, 2002
, 8(3)
: 306
-314
.
DOI: 10.61558/2993-074X.1464
Single_phase solid solution of LiNi 0.8- x Al x Co 0.2 O 2 (0≤ x <0.1)had been synthesized and characterized by X_ray diffraction(XRD) and scanning electron microscopy (SEM). Their electrochemical performance was examined by charge_discharge cycling.The LiNi 0.71 Al 0.09 Co 0.2 O 2 compound showed a discharge capacity of 152 mAh/g after 20 cycles that corresponds to 97.4% capacity retention. The beneficial effect of co_doping with Al and Co elements was corro_borated by slow scanning cyclic voltammograms(SSCV),electrochemical impedance spectrum(EIS)and differential scanning calorimetry(DSC) data on charged cathodes. These results show that the 2D_character of the crystal lattice was stabilized by co_doping with Al and Co, the phase transitions that occur during deintercalation or intercalation of Li_ions were significantly suppressed,and thermal stability in the charged state was also improved.
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