To enhance the electrochemical performance of lithium-ion battery anodes with higher silicon content,it is essential to engineer their microstructure for better lithium-ion transport and mitigated volume change as wel...To enhance the electrochemical performance of lithium-ion battery anodes with higher silicon content,it is essential to engineer their microstructure for better lithium-ion transport and mitigated volume change as well.Herein,we suggest an effective approach to control the micropore structure of silicon oxide(SiO_(x))/artificial graphite(AG)composite electrodes using a perforated current collector.The electrode features a unique pore structure,where alternating high-porosity domains and low-porosity domains markedly reduce overall electrode resistance,leading to a 20%improvement in rate capability at a 5C-rate discharge condition.Using microstructure-resolved modeling and simulations,we demonstrate that the patterned micropore structure enhances lithium-ion transport,mitigating the electrolyte concentration gradient of lithium-ion.Additionally,perforating current collector with a chemical etching process increases the number of hydrogen bonding sites and enlarges the interface with the SiO_(x)/AG composite electrode,significantly improving adhesion strength.This,in turn,suppresses mechanical degradation and leads to a 50%higher capacity retention.Thus,regularly arranged micropore structure enabled by the perforated current collector successfully improves both rate capability and cycle life in SiO_(x)/AG composite electrodes,providing valuable insights into electrode engineering.展开更多
In recent years,researches on improving high-voltage performance of lithium-ion batteries incorporating LiNi_(0.5)Co_(0.2)Mn_(0.3)O_(2)(NCM523)and artificial graphite(AG)have been widely reported.However,limited atten...In recent years,researches on improving high-voltage performance of lithium-ion batteries incorporating LiNi_(0.5)Co_(0.2)Mn_(0.3)O_(2)(NCM523)and artificial graphite(AG)have been widely reported.However,limited attentions have been paid to understand the effects and influence mechanisms of charge and discharge rates and charge limit currents on cyclability of NCM523/AG cells.Herein,a∼1.9 Ah NCM523/AG pouch cell is employed,whose electrochemical and structural evolutions after 800 cycles at various rates are comprehensively investigated.We find that cycling performances are strongly influenced by charge rate,followed by limit current and discharge rate.The cell charged at a high rate and cell charged until reaching a low limit current both exhibit low capacity retentions compared to the cell discharged at a high rate.Possible failure reasons are analyzed by advanced characterizations.Results reveal that NCM523 cathodes of the cells deteriorated early experience severe transition metal dissolution,lattice distortion,and partial phase transformation.Meanwhile,the deposited transition metals on AG anodes catalyze the electrolyte consumption,lithium plating and active area loss.Finally,these side reactions notably increase cell impedance and electrochemical polarization.Undoubtedly,these findings clearly outline the challenges and optimization direction for high-rate NCM523/AG cells.展开更多
A tin oxide and carbon composite （Sn6O4（OH）4/AG） with a Sn content of 0.15-0.30 was prepared by chemical deposition at normal pressures and temperatures. The structures of the artificial graphite （AG）, the Sn6O4...A tin oxide and carbon composite （Sn6O4（OH）4/AG） with a Sn content of 0.15-0.30 was prepared by chemical deposition at normal pressures and temperatures. The structures of the artificial graphite （AG）, the Sn6O4（OH）4, and the Sn6O4（OH）4JAG were analyzed using X-ray diffraction. The electrochemical lithiation was investigated by measuring the galvanostatic charge and discharge ratio. The electrochemical capacities of the three materials during the first discharge were 310 mAh/g （AG）, 616 mAh/g （Sn6O4（OH）4/AG）, and 1090 mAh/g （Sn6O4（oa）4）. The discharge capacity of the Sn6O4（OH）4/AG was larger than the simple sum of the capacities provided by AG and Sn6O4（OH）4 with the same content. The cyclic performance of Sn6O4（OH）4/AG was also better than that of Sn6O4（OH）4 for voltages of 0 to 3 V. The results imply that the interaction between Sn and C in Sn6O4（OH）4/AG is very strong and effectively inhibits the volume expansion of the Sn.展开更多
基金supported by the National Research Foundation of Korea(NRF)grant funded by the Korean government(MSIT)(No.NRF-2021M3H4A1A02048529)the Ministry of Trade,Industry and Energy(MOTIE)of the Korean government under grant No.RS-2022-00155854support from the DGIST Supercomputing and Big Data Center.
文摘To enhance the electrochemical performance of lithium-ion battery anodes with higher silicon content,it is essential to engineer their microstructure for better lithium-ion transport and mitigated volume change as well.Herein,we suggest an effective approach to control the micropore structure of silicon oxide(SiO_(x))/artificial graphite(AG)composite electrodes using a perforated current collector.The electrode features a unique pore structure,where alternating high-porosity domains and low-porosity domains markedly reduce overall electrode resistance,leading to a 20%improvement in rate capability at a 5C-rate discharge condition.Using microstructure-resolved modeling and simulations,we demonstrate that the patterned micropore structure enhances lithium-ion transport,mitigating the electrolyte concentration gradient of lithium-ion.Additionally,perforating current collector with a chemical etching process increases the number of hydrogen bonding sites and enlarges the interface with the SiO_(x)/AG composite electrode,significantly improving adhesion strength.This,in turn,suppresses mechanical degradation and leads to a 50%higher capacity retention.Thus,regularly arranged micropore structure enabled by the perforated current collector successfully improves both rate capability and cycle life in SiO_(x)/AG composite electrodes,providing valuable insights into electrode engineering.
基金We thank the Natural Science Foundation of Zhejiang Province,China(grant Nos.LQ21B030004 and LQ21E040001)the National Natural Science Foundation of China(grant No.12147219)。
文摘In recent years,researches on improving high-voltage performance of lithium-ion batteries incorporating LiNi_(0.5)Co_(0.2)Mn_(0.3)O_(2)(NCM523)and artificial graphite(AG)have been widely reported.However,limited attentions have been paid to understand the effects and influence mechanisms of charge and discharge rates and charge limit currents on cyclability of NCM523/AG cells.Herein,a∼1.9 Ah NCM523/AG pouch cell is employed,whose electrochemical and structural evolutions after 800 cycles at various rates are comprehensively investigated.We find that cycling performances are strongly influenced by charge rate,followed by limit current and discharge rate.The cell charged at a high rate and cell charged until reaching a low limit current both exhibit low capacity retentions compared to the cell discharged at a high rate.Possible failure reasons are analyzed by advanced characterizations.Results reveal that NCM523 cathodes of the cells deteriorated early experience severe transition metal dissolution,lattice distortion,and partial phase transformation.Meanwhile,the deposited transition metals on AG anodes catalyze the electrolyte consumption,lithium plating and active area loss.Finally,these side reactions notably increase cell impedance and electrochemical polarization.Undoubtedly,these findings clearly outline the challenges and optimization direction for high-rate NCM523/AG cells.
文摘A tin oxide and carbon composite （Sn6O4（OH）4/AG） with a Sn content of 0.15-0.30 was prepared by chemical deposition at normal pressures and temperatures. The structures of the artificial graphite （AG）, the Sn6O4（OH）4, and the Sn6O4（OH）4JAG were analyzed using X-ray diffraction. The electrochemical lithiation was investigated by measuring the galvanostatic charge and discharge ratio. The electrochemical capacities of the three materials during the first discharge were 310 mAh/g （AG）, 616 mAh/g （Sn6O4（OH）4/AG）, and 1090 mAh/g （Sn6O4（oa）4）. The discharge capacity of the Sn6O4（OH）4/AG was larger than the simple sum of the capacities provided by AG and Sn6O4（OH）4 with the same content. The cyclic performance of Sn6O4（OH）4/AG was also better than that of Sn6O4（OH）4 for voltages of 0 to 3 V. The results imply that the interaction between Sn and C in Sn6O4（OH）4/AG is very strong and effectively inhibits the volume expansion of the Sn.
