Composite cathodes integrating Ni-rich layered oxides and oxide solid electrolytes are essential for highenergy all-solid-state lithium-ion batteries(ASSLBs),yet interfacial degradation during high-temperature co-sint...Composite cathodes integrating Ni-rich layered oxides and oxide solid electrolytes are essential for highenergy all-solid-state lithium-ion batteries(ASSLBs),yet interfacial degradation during high-temperature co-sintering(>600℃)remains a critical challenge.While surface passivation strategies mitigate reactions below 400℃,their effectiveness diminishes at elevated temperatures due to inability to counteract Li^(+)concentration gradients.Here,we introduce in situ lithium compensators,i.e.,LiOH/Li_(2)CO_(3),into NCM-LATP composite cathodes to dynamically replenish Li^(+)during co-sintering.These additives melt to form transient Li^(+)-rich phases that back-diffuse Li^(+)into NCM lattices,suppressing layered-to-rock salt transitions and stabilizing the interface.Quasi in situ XRD confirms retention of the layered structure at temperature up to 700℃,while electrochemical tests demonstrate a reversible capacity of 222.2 mA h g^(-1)—comparable to NCM before co-sintering—and an impressive 65.3% capacity retention improvement over100 cycles.In contrast,uncompensated cathodes exhibit severe degradation to 96.5 mA h g^(-1)due to Li depletion and resistive Li-Ti-O interphases.This strategy integrates sacrificial chemistry with scalable powder-mixing workflows,achieving a 93.4% reduction in interfacial impedance.By addressing Li^(+)flux homogenization and structural stability,this work provides a practical pathway toward industrialscale fabrication of high-performance ASSLBs.展开更多
The Thyristor-Controlled Series Compensator(TCSC)presents an effective solution for mitigating transmission congestion in power systems by regulating the distribution of line power flow.However,inherent faults within ...The Thyristor-Controlled Series Compensator(TCSC)presents an effective solution for mitigating transmission congestion in power systems by regulating the distribution of line power flow.However,inherent faults within the TCSC may lead to an unintended intensification of transmission congestion in other sections of the system post-installation,resulting in non-coherent phenomena of line blocking.In response to this challenge,this paper introduces a novel two-stage site selectionmethod for TCSC,emphasizing the enhancement of coherence in addressing line-blocking issues.Through rigorous non-coherent verification,this method mitigates the risk of line congestion deterioration due to TCSC faults.In the initial stage of the proposed method,TCSC faults are not considered during the extraction of system states.System state analysis is performed based on the TCSC site selection model,aiming to minimize system load reduction.The preliminary recommended installation position for TCSC is determined by sorting the frequency of TCSC installation occurrences on lines extracted from the analyzed system states.In the subsequent stage,accounting for the influence of TCSC faults on line faults,system operating states are extracted.Line and system congestion indices are calculated through the statistical analysis of the system state analysis results.The installation of TCSC at the preliminary position is scrutinized to identify non-coherent phenomena of line congestion on other lines.If such phenomena are observed,the installation position is excluded,and the TCSC site selection process is reinitiated based on the methodology from the first stage.To validate the effectiveness of the proposed method,a case study is conducted on a modified RBTS test system.The case study results indicate that,compared with TCSC siting schemes that do not consider transmission congestion non-coherency,the proposed non-coherency-based siting scheme reduces the system congestion expectation(SCE)and system congestion probability(SCP)by 17.7%and 11.4%,respectively,while lowering the LOLP and EENS by 2.56% and 4.55%,respectively.These results demonstrate that the proposed method can effectively alleviate transmission congestion and enhance the overall reliability of the system.展开更多
跟-构网型(grid following and grid-forming,GFL-GFM)变流器混合并网系统中多类型控制策略及控制切换行为使电压响应特性复杂多变,难以快速、准确评估其暂态电压稳定状态。为此,该文提出一种基于切换系统最大李雅普诺夫指数(switching ...跟-构网型(grid following and grid-forming,GFL-GFM)变流器混合并网系统中多类型控制策略及控制切换行为使电压响应特性复杂多变,难以快速、准确评估其暂态电压稳定状态。为此,该文提出一种基于切换系统最大李雅普诺夫指数(switching system maximum Lyapunov exponent,SSMLE)的跟-构网型变流器混合并网系统暂态电压稳定评估方法。首先,计及系统多运行状态和运行参数对暂态电压响应特性影响,建立混合并网系统不同运行工况下电压轨线变分方程;然后,在各运行状态下通过变分方程分段求解SSMLE,并采用切换补偿矩阵修正控制切换时刻积分终值矩阵偏差,提升电压稳定状态判别速度和准确度;其次,利用SSMLE分析系统关键参数对暂态电压稳定性的影响并确定暂态电压稳定参数域,可为调度人员获取系统运行状态、更新电压稳控策略提供参考;最后,通过GFL-GFM变流器混合并网系统和多机硬件在环仿真系统的仿真分析,验证所提方法的准确性和有效性。展开更多
基金financially supported by the National Natural Science Foundation of China(52102206)the Natural Science Foundation of Beijing Municipality-Shunyi Innovation Collaborative Joint Fund(L247018)+2 种基金the Natural Science Foundation of Beijing Municipality(2254076 and 2252024)the Central Guidance on Local Science and Technology Development Fund of Hebei Province(246Z4412G)the Fundamental Research Funds for the Central Universities(2025MS022,North China Electric Power University)。
文摘Composite cathodes integrating Ni-rich layered oxides and oxide solid electrolytes are essential for highenergy all-solid-state lithium-ion batteries(ASSLBs),yet interfacial degradation during high-temperature co-sintering(>600℃)remains a critical challenge.While surface passivation strategies mitigate reactions below 400℃,their effectiveness diminishes at elevated temperatures due to inability to counteract Li^(+)concentration gradients.Here,we introduce in situ lithium compensators,i.e.,LiOH/Li_(2)CO_(3),into NCM-LATP composite cathodes to dynamically replenish Li^(+)during co-sintering.These additives melt to form transient Li^(+)-rich phases that back-diffuse Li^(+)into NCM lattices,suppressing layered-to-rock salt transitions and stabilizing the interface.Quasi in situ XRD confirms retention of the layered structure at temperature up to 700℃,while electrochemical tests demonstrate a reversible capacity of 222.2 mA h g^(-1)—comparable to NCM before co-sintering—and an impressive 65.3% capacity retention improvement over100 cycles.In contrast,uncompensated cathodes exhibit severe degradation to 96.5 mA h g^(-1)due to Li depletion and resistive Li-Ti-O interphases.This strategy integrates sacrificial chemistry with scalable powder-mixing workflows,achieving a 93.4% reduction in interfacial impedance.By addressing Li^(+)flux homogenization and structural stability,this work provides a practical pathway toward industrialscale fabrication of high-performance ASSLBs.
基金supported by Graduate Research and Innovation Program Project of Nanjing Institute of Technology(No.TB202517078).
文摘The Thyristor-Controlled Series Compensator(TCSC)presents an effective solution for mitigating transmission congestion in power systems by regulating the distribution of line power flow.However,inherent faults within the TCSC may lead to an unintended intensification of transmission congestion in other sections of the system post-installation,resulting in non-coherent phenomena of line blocking.In response to this challenge,this paper introduces a novel two-stage site selectionmethod for TCSC,emphasizing the enhancement of coherence in addressing line-blocking issues.Through rigorous non-coherent verification,this method mitigates the risk of line congestion deterioration due to TCSC faults.In the initial stage of the proposed method,TCSC faults are not considered during the extraction of system states.System state analysis is performed based on the TCSC site selection model,aiming to minimize system load reduction.The preliminary recommended installation position for TCSC is determined by sorting the frequency of TCSC installation occurrences on lines extracted from the analyzed system states.In the subsequent stage,accounting for the influence of TCSC faults on line faults,system operating states are extracted.Line and system congestion indices are calculated through the statistical analysis of the system state analysis results.The installation of TCSC at the preliminary position is scrutinized to identify non-coherent phenomena of line congestion on other lines.If such phenomena are observed,the installation position is excluded,and the TCSC site selection process is reinitiated based on the methodology from the first stage.To validate the effectiveness of the proposed method,a case study is conducted on a modified RBTS test system.The case study results indicate that,compared with TCSC siting schemes that do not consider transmission congestion non-coherency,the proposed non-coherency-based siting scheme reduces the system congestion expectation(SCE)and system congestion probability(SCP)by 17.7%and 11.4%,respectively,while lowering the LOLP and EENS by 2.56% and 4.55%,respectively.These results demonstrate that the proposed method can effectively alleviate transmission congestion and enhance the overall reliability of the system.
文摘跟-构网型(grid following and grid-forming,GFL-GFM)变流器混合并网系统中多类型控制策略及控制切换行为使电压响应特性复杂多变,难以快速、准确评估其暂态电压稳定状态。为此,该文提出一种基于切换系统最大李雅普诺夫指数(switching system maximum Lyapunov exponent,SSMLE)的跟-构网型变流器混合并网系统暂态电压稳定评估方法。首先,计及系统多运行状态和运行参数对暂态电压响应特性影响,建立混合并网系统不同运行工况下电压轨线变分方程;然后,在各运行状态下通过变分方程分段求解SSMLE,并采用切换补偿矩阵修正控制切换时刻积分终值矩阵偏差,提升电压稳定状态判别速度和准确度;其次,利用SSMLE分析系统关键参数对暂态电压稳定性的影响并确定暂态电压稳定参数域,可为调度人员获取系统运行状态、更新电压稳控策略提供参考;最后,通过GFL-GFM变流器混合并网系统和多机硬件在环仿真系统的仿真分析,验证所提方法的准确性和有效性。
