高比容量Li2ZnTi3O8@C⁃N负极材料储锂性能研究

Li⁃Storage of Li2ZnTi3O8@C⁃N Anode Materials with High Specific Capacities

沈紫烨 王利娟

Ziye Shen Lijuan Wang

辽宁石油化工大学 石油化工学院，辽宁 抚顺 113001

School of Petrochemical Engineering，Liaoning Petrochemical University，Fushun Liaoning 113001

以盐酸多巴胺为N、C源，高温固相法合成N掺杂C包覆Li2ZnTi3O8@C?N负极材料。在合成过程中发现，部分Ti4+被还原为Ti3+，达到了包覆和掺杂共同改性的目的。该方法有利于提高离子扩散系数和降低电荷转移电阻。在电流密度为0.5、1.0、1.5、2.0、2.5、3.0 A/g时，Li2ZnTi3O8@C?N?2的放电比容量分别超过240.0、220.0、210.0、200.0、190.0、180.0 mA ?h/g。还研究了N掺杂C包覆Li2ZnTi3O8复合材料的低温电化学性能。结果表明，0 ℃时该样品的放电比容量远高于未改性的Li2ZnTi3O8负极材料；电流密度为0.2 A/g时的首次放电比容量为262.5 mA ?h/g，循环300次后放电比容量为241.7 mA ?h/g；在电流密度为1.0 A/g、循环300次后放电比容量依然有147.4 mA ?h/g。

Li2ZnTi3O8 anodes coated with N?doped carbon from dopamine hydrochloride were synthesized via a high?temperature solid?state method.Some Ti4+ ions were reduced to Ti3+ ions during synthesis,which enabled the co?modification of coating and doping.The modification method can enhance the ion diffusion coefficients and reduce the charge?transfer resistance.In the rate performance tests at 0.5,1.0,1.5,2.0,2.5,3.0 A/g,the specific capacities of N?doped carbon?coated Li2ZnTi3O8(Li2ZnTi3O8@C?N?2) are over 240.0，220.0，210.0，200.0，190.0，180.0 mA ?h/g,respectively.In addition,the electrochemical performance of this material at a low temperature was also studied.The results show that the Li2ZnTi3O8@C?N?2 sample has much higher discharge specific capacities than those of unmodified Li2ZnTi3O8 anode material at 0 ℃.The initial discharge specific capacity is 262.5 mA ?h/g at 0.2 A/g,and the discharge specific capacity of 241.7 mA ?h/g is still obtained after 300 cycles.Even at 1.0 A/g,the discharge specific capacity is kept at 147.4 mA ?h/g after 300 cycles.

辽宁省“兴辽英才计划”项目(XLYC1907025);辽宁石油化工大学第五层次人才基金项目(2018XJJ?012)

10.3969/j.issn.1006-396X.2022.03.001