High-capacity nickel-rich layered oxides are promising cathode materials for high-energy-density lithium batteries.However,the poor structural stability and severe side reactions at the electrode/electrolyte interface...High-capacity nickel-rich layered oxides are promising cathode materials for high-energy-density lithium batteries.However,the poor structural stability and severe side reactions at the electrode/electrolyte interface result in unsatisfactory cycle performance.Herein,the thin layer of two-dimensional(2D)graphitic carbon-nitride(g-C_(3)N_(4))is uniformly coated on the LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(denoted as NCM811@CN)using a facile chemical vaporization-assisted synthesis method.As an ideal protective layer,the g-C_(3)N_(4)layer effectively avoids direct contact between the NCM811 cathode and the electrolyte,preventing harmful side reactions and inhibiting secondary crystal cracking.Moreover,the unique nanopore structure and abundant nitrogen vacancy edges in g-C_(3)N_(4)facilitate the adsorption and diffusion of lithium ions,which enhances the lithium deintercalation/intercalation kinetics of the NCM811 cathode.As a result,the NCM811@CN-3wt%cathode exhibits 161.3 mAh g^(−1)and capacity retention of 84.6%at 0.5 C and 55°C after 400 cycles and 95.7 mAh g^(−1)at 10 C,which is greatly superior to the uncoated NCM811(i.e.129.3 mAh g^(−1)and capacity retention of 67.4%at 0.5 C and 55°C after 220 cycles and 28.8 mAh g^(−1)at 10 C).The improved cycle performance of the NCM811@CN-3wt%cathode is also applicable to solid–liquid-hybrid cells composed of PVDF:LLZTO electrolyte membranes,which show 163.8 mAh g^(−1)and the capacity retention of 88.1%at 0.1 C and 30°C after 200 cycles and 95.3 mAh g^(−1)at 1 C.展开更多
从制备方法到形貌控制的角度着手,使用水热法制备性能稳定的LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)正极材料并对其电化学性能进行分析。采用草酸(H2C2O4)、碳酸氢铵(NH4HCO3)和尿素(CON2H4)作为沉淀剂和螯合剂,使用不同的Ni、Co、Mn过渡金属...从制备方法到形貌控制的角度着手,使用水热法制备性能稳定的LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)正极材料并对其电化学性能进行分析。采用草酸(H2C2O4)、碳酸氢铵(NH4HCO3)和尿素(CON2H4)作为沉淀剂和螯合剂,使用不同的Ni、Co、Mn过渡金属盐作为原材料,利用水热法制备出新颖的棒状形貌、球形形貌和椭球形形貌的LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)正极材料,并对正极材料进行电化学测试。结果表明,棒状形貌、球形形貌和椭球形形貌的正极材料都具有优异的循环性能,其中椭球状材料的电化学性能最好(当在充放电倍率为20 m A/g,电压范围在2.8~4.3 V时,首次放电比容量为175.04m Ah/g,最高放电比容量为188.78 m Ah/g,容量保持率为88.7%,在倍率为2000 m A/g时放电比容量达到115.47m Ah/g)。展开更多
基金supported by the National Key R&D Program of China(Grant No.2023YFB2503900)the National Natural Science Foundation of China(Grant No.52372203)+1 种基金the National Natural Science Foundation of China(Grant No.52202259)the Shandong Province Natural Science Foundation(ZR2022QE093).
文摘High-capacity nickel-rich layered oxides are promising cathode materials for high-energy-density lithium batteries.However,the poor structural stability and severe side reactions at the electrode/electrolyte interface result in unsatisfactory cycle performance.Herein,the thin layer of two-dimensional(2D)graphitic carbon-nitride(g-C_(3)N_(4))is uniformly coated on the LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(denoted as NCM811@CN)using a facile chemical vaporization-assisted synthesis method.As an ideal protective layer,the g-C_(3)N_(4)layer effectively avoids direct contact between the NCM811 cathode and the electrolyte,preventing harmful side reactions and inhibiting secondary crystal cracking.Moreover,the unique nanopore structure and abundant nitrogen vacancy edges in g-C_(3)N_(4)facilitate the adsorption and diffusion of lithium ions,which enhances the lithium deintercalation/intercalation kinetics of the NCM811 cathode.As a result,the NCM811@CN-3wt%cathode exhibits 161.3 mAh g^(−1)and capacity retention of 84.6%at 0.5 C and 55°C after 400 cycles and 95.7 mAh g^(−1)at 10 C,which is greatly superior to the uncoated NCM811(i.e.129.3 mAh g^(−1)and capacity retention of 67.4%at 0.5 C and 55°C after 220 cycles and 28.8 mAh g^(−1)at 10 C).The improved cycle performance of the NCM811@CN-3wt%cathode is also applicable to solid–liquid-hybrid cells composed of PVDF:LLZTO electrolyte membranes,which show 163.8 mAh g^(−1)and the capacity retention of 88.1%at 0.1 C and 30°C after 200 cycles and 95.3 mAh g^(−1)at 1 C.
文摘从制备方法到形貌控制的角度着手,使用水热法制备性能稳定的LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)正极材料并对其电化学性能进行分析。采用草酸(H2C2O4)、碳酸氢铵(NH4HCO3)和尿素(CON2H4)作为沉淀剂和螯合剂,使用不同的Ni、Co、Mn过渡金属盐作为原材料,利用水热法制备出新颖的棒状形貌、球形形貌和椭球形形貌的LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)正极材料,并对正极材料进行电化学测试。结果表明,棒状形貌、球形形貌和椭球形形貌的正极材料都具有优异的循环性能,其中椭球状材料的电化学性能最好(当在充放电倍率为20 m A/g,电压范围在2.8~4.3 V时,首次放电比容量为175.04m Ah/g,最高放电比容量为188.78 m Ah/g,容量保持率为88.7%,在倍率为2000 m A/g时放电比容量达到115.47m Ah/g)。
