Pub Date : 2024-08-08DOI: 10.1149/1945-7111/ad6d00
Xinxin Hu, Fan Zhang, Junyuan Zhong, Xucheng Wang, Xiangling Tong
Designing and synthesizing aqueous zinc ion battery cathode materials with high specific capacity and stability remains a significant challenge. In this study, citric acid was selected as the reducing agent for converting V2O5 to VO2 within a carbon matrix using the hydrothermal method. Citric acid acts as a nucleocrystal, forming nanoparticles through self-assembly from within, creating a distinct micromorphological structure in V4+ materials. It exhibits excellent electrochemical performance as a cathode material for aqueous zinc ion batteries, showing a high specific capacity of 399.33 mAh g-1 at 1A g-1, and a capacity retention of up to 98.3% after cycling for 1000 cycles at a high current density of 5A g-1.
{"title":"VO2-C Materials Prepared from Citric Acid Organic Skeleton as C Matrix as Anode for Aqueous Zinc Ion Batteries","authors":"Xinxin Hu, Fan Zhang, Junyuan Zhong, Xucheng Wang, Xiangling Tong","doi":"10.1149/1945-7111/ad6d00","DOIUrl":"https://doi.org/10.1149/1945-7111/ad6d00","url":null,"abstract":"\u0000 Designing and synthesizing aqueous zinc ion battery cathode materials with high specific capacity and stability remains a significant challenge. In this study, citric acid was selected as the reducing agent for converting V2O5 to VO2 within a carbon matrix using the hydrothermal method. Citric acid acts as a nucleocrystal, forming nanoparticles through self-assembly from within, creating a distinct micromorphological structure in V4+ materials. It exhibits excellent electrochemical performance as a cathode material for aqueous zinc ion batteries, showing a high specific capacity of 399.33 mAh g-1 at 1A g-1, and a capacity retention of up to 98.3% after cycling for 1000 cycles at a high current density of 5A g-1.","PeriodicalId":17364,"journal":{"name":"Journal of The Electrochemical Society","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141925650","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
O3-type NaNi0.4Fe0.2Mn0.4O2 cathode materials are structurally stable and have a high nickel content, allowing for stable high-capacity output. However, their performance needs further improvement. First, we investigated the effects of different sodium contents on the structure, morphology, and electrochemical performance of NaxNi0.4Fe0.2Mn0.4O2(x=0.85, 0.9, 0.95, 1, 1.05) materials. The Na0.9Ni0.4Fe0.2Mn0.4O2 material exhibited initial discharge specific capacities of 148.11 and 181.80 mAh·g-1 at voltage ranges of 2-4.1 V and 2-4.2 V, respectively. To further optimize the cycling performance of the material, we doped NaNi0.4Fe0.2Mn0.4O2 with different calcium contents. Ca2+ doping significantly enhanced the electrochemical performance of the material. Subsequently, we synthesized Na0.96Ca0.02(NMF)0.95Zn0.05O2, and the dual-doped NMF-Ca0.02Zn0.05 maintains approximately 80% capacity retention at 1-4.05 V, and around 70% as the cut-off voltage increases to 4.15 V in full cells.
O3 型 NaNi0.4Fe0.2Mn0.4O2 阴极材料结构稳定，镍含量高，可实现稳定的高容量输出。然而，它们的性能还需要进一步提高。首先，我们研究了不同钠含量对 NaxNi0.4Fe0.2Mn0.4O2（x=0.85、0.9、0.95、1、1.05）材料的结构、形态和电化学性能的影响。Na0.9Ni0.4Fe0.2Mn0.4O2 材料在 2-4.1 V 和 2-4.2 V 电压范围内的初始放电比容量分别为 148.11 和 181.80 mAh-g-1。为了进一步优化材料的循环性能，我们在 NaNi0.4Fe0.2Mn0.4O2 中掺入了不同含量的钙。Ca2+ 的掺杂大大提高了材料的电化学性能。随后，我们合成了 Na0.96Ca0.02(NMF)0.95Zn0.05O2，双掺杂 NMF-Ca0.02Zn0.05 在 1-4.05 V 电压下可保持约 80% 的容量保持率，而在完整电池中，当截止电压升高到 4.15 V 时，容量保持率约为 70%。
{"title":"Preparation and Property Optimization of High Capacity O3-type NaNi0.4Fe0.2Mn0.4O2","authors":"Xiaoning Li, Mengmeng Liu, Wenjuan Zhang, Yanli Zhang, Jiakun Zhou, Wenzhang Zhou, Naixin Wang, Weiwei Xu, KeHua Dai","doi":"10.1149/1945-7111/ad6cfa","DOIUrl":"https://doi.org/10.1149/1945-7111/ad6cfa","url":null,"abstract":"\u0000 O3-type NaNi0.4Fe0.2Mn0.4O2 cathode materials are structurally stable and have a high nickel content, allowing for stable high-capacity output. However, their performance needs further improvement. First, we investigated the effects of different sodium contents on the structure, morphology, and electrochemical performance of NaxNi0.4Fe0.2Mn0.4O2(x=0.85, 0.9, 0.95, 1, 1.05) materials. The Na0.9Ni0.4Fe0.2Mn0.4O2 material exhibited initial discharge specific capacities of 148.11 and 181.80 mAh·g-1 at voltage ranges of 2-4.1 V and 2-4.2 V, respectively. To further optimize the cycling performance of the material, we doped NaNi0.4Fe0.2Mn0.4O2 with different calcium contents. Ca2+ doping significantly enhanced the electrochemical performance of the material. Subsequently, we synthesized Na0.96Ca0.02(NMF)0.95Zn0.05O2, and the dual-doped NMF-Ca0.02Zn0.05 maintains approximately 80% capacity retention at 1-4.05 V, and around 70% as the cut-off voltage increases to 4.15 V in full cells.","PeriodicalId":17364,"journal":{"name":"Journal of The Electrochemical Society","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141927080","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-08DOI: 10.1149/1945-7111/ad6cfc
Divya Rathore, Ning Zhang, Nafiseh Zaker, babak shalchiamirkhiz, Animesh Dutta, Hassan Tariq, Jeff R. Dahn
Nickel and manganese-based layered oxides with a nickel content ranging from 50% to 80% are promising cathode materials for high-energy density lithium-ion batteries. However, these materials face challenges such as poor rate capability and limited cycling stability. The addition of excess lithium can mitigate these issues to some extent. This study examines the impact of incorporating small amounts of cobalt (5% or 10%) into these materials through an “all-dry” synthesis approach in stoichiometric and excess lithium-containing compositions. Results indicate that adding even these small amounts of cobalt decreases the cation mixing, improves crystallinity, reduces electronic resistance, and influences the morphology depending on whether nickel or manganese is replaced. The materials can accommodate up to 15% excess lithium without significant surface impurities. The addition of cobalt further enhances the rate capability of the material in excess lithium materials, but increasing cobalt content tends to compromise cycling stability when the materials are cycled up to 4.4 V. Materials in which 5% cobalt replaces nickel still exhibit superior rate capability and cycling performance compared to materials without cobalt. Therefore, incorporating small amounts of cobalt can positively impact the performance of Li1+x(Ni0.6Mn0.4)1-xO2 materials, offering a balance between improved rate capability and cycling stability.
{"title":"Impact of Cobalt Addition on Single-Crystal Li1+x(Ni0.6Mn0.4)1-xO2 Cathode Material Performance","authors":"Divya Rathore, Ning Zhang, Nafiseh Zaker, babak shalchiamirkhiz, Animesh Dutta, Hassan Tariq, Jeff R. Dahn","doi":"10.1149/1945-7111/ad6cfc","DOIUrl":"https://doi.org/10.1149/1945-7111/ad6cfc","url":null,"abstract":"\u0000 Nickel and manganese-based layered oxides with a nickel content ranging from 50% to 80% are promising cathode materials for high-energy density lithium-ion batteries. However, these materials face challenges such as poor rate capability and limited cycling stability. The addition of excess lithium can mitigate these issues to some extent. This study examines the impact of incorporating small amounts of cobalt (5% or 10%) into these materials through an “all-dry” synthesis approach in stoichiometric and excess lithium-containing compositions. Results indicate that adding even these small amounts of cobalt decreases the cation mixing, improves crystallinity, reduces electronic resistance, and influences the morphology depending on whether nickel or manganese is replaced. The materials can accommodate up to 15% excess lithium without significant surface impurities. The addition of cobalt further enhances the rate capability of the material in excess lithium materials, but increasing cobalt content tends to compromise cycling stability when the materials are cycled up to 4.4 V. Materials in which 5% cobalt replaces nickel still exhibit superior rate capability and cycling performance compared to materials without cobalt. Therefore, incorporating small amounts of cobalt can positively impact the performance of Li1+x(Ni0.6Mn0.4)1-xO2 materials, offering a balance between improved rate capability and cycling stability.","PeriodicalId":17364,"journal":{"name":"Journal of The Electrochemical Society","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141928690","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-08DOI: 10.1149/1945-7111/ad6cfd
Luiza Streck, T. Roth, Hannah Bosch, Cedric Kirst, Mathias Rehm, Peter Keil, A. Jossen
The calendar aging and self-discharge behavior of Na-Ion cells containing a layered oxide NaNi1/3Fe1/3Mn1/3 (NFM) cathode were investigated and compared to two Li-Ion cell chemistries, G/LiFePO4 (LFP) and SiG/LiNi0.8Mn0.1Co0.1O2 (NMC811). The self-discharge measurements were performed via voltage hold experiments at different states of charge (10%, 40%, 50%, 70%, 90%, and 100%) and temperatures (25°C, 40°C, and 55°C). A high-precision coulometry analysis was conducted to investigate the coulombic efficiency (CE), differential voltage analysis (DVA), and end-point slippage. The results show that the Na-Ion cells present a similar self-discharge behavior to the NMC811 Li-Ion cells. In addition, via CE and end-point slippage analysis, strong reversible reactions were observed for the Na-Ion cells. Despite the poor CE values, the cells presented a low capacity loss. Post-mortem analysis showed sodium plating on the edges of all the SOCs investigated. The LFP results presented mainly calendar losses from lithium inventory loss with almost no cathode-related degradation. At high SOCs, both transition metal cathodes, NMC811 Li-Ion and NFM Na-Ion, exhibited more cathode-related processes dominating the self-discharge current and presumably improving the capacity retention due to electrolyte oxidation. Finally, the Na-Ion cells showed anode overhang equalization effects like Li-Ion cells.
研究了含有层状氧化物 NaNi1/3Fe1/3Mn1/3（NFM）阴极的钠离子电池的日历老化和自放电行为，并将其与两种锂离子电池化学成分（G/LiFePO4（LFP）和 SiG/LiNi0.8Mn0.1Co0.1O2 (NMC811)）进行了比较。自放电测量是在不同的充电状态（10%、40%、50%、70%、90% 和 100% ）和温度（25°C、40°C 和 55°C）下通过电压保持实验进行的。为了研究库仑效率（CE）、差分电压分析（DVA）和终点滑移，还进行了高精度库仑测量分析。结果表明，钠离子电池的自放电行为与 NMC811 锂离子电池相似。此外，通过 CE 和端点滑移分析，还观察到钠离子电池发生了强烈的可逆反应。尽管 CE 值较差，但电池的容量损失较低。死后分析表明，所有被研究的 SOC 边缘都有钠镀层。LFP 结果主要显示了锂库存损失造成的日历损失，几乎没有与正极相关的降解。在高 SOC 条件下，NMC811 锂离子电池和 NFM 钠离子电池这两种过渡金属阴极都显示出更多与阴极相关的过程，这些过程主导了自放电电流，并可能由于电解质氧化而提高了容量保持率。最后，与锂离子电池一样， Na 离子电池也表现出阳极悬垂均衡效应。
{"title":"Self-Discharge and Calendar Aging Behavior of Li-Ion and Na-Ion Cells","authors":"Luiza Streck, T. Roth, Hannah Bosch, Cedric Kirst, Mathias Rehm, Peter Keil, A. Jossen","doi":"10.1149/1945-7111/ad6cfd","DOIUrl":"https://doi.org/10.1149/1945-7111/ad6cfd","url":null,"abstract":"\u0000 The calendar aging and self-discharge behavior of Na-Ion cells containing a layered oxide NaNi1/3Fe1/3Mn1/3 (NFM) cathode were investigated and compared to two Li-Ion cell chemistries, G/LiFePO4 (LFP) and SiG/LiNi0.8Mn0.1Co0.1O2 (NMC811). The self-discharge measurements were performed via voltage hold experiments at different states of charge (10%, 40%, 50%, 70%, 90%, and 100%) and temperatures (25°C, 40°C, and 55°C). A high-precision coulometry analysis was conducted to investigate the coulombic efficiency (CE), differential voltage analysis (DVA), and end-point slippage. The results show that the Na-Ion cells present a similar self-discharge behavior to the NMC811 Li-Ion cells. In addition, via CE and end-point slippage analysis, strong reversible reactions were observed for the Na-Ion cells. Despite the poor CE values, the cells presented a low capacity loss. Post-mortem analysis showed sodium plating on the edges of all the SOCs investigated. The LFP results presented mainly calendar losses from lithium inventory loss with almost no cathode-related degradation. At high SOCs, both transition metal cathodes, NMC811 Li-Ion and NFM Na-Ion, exhibited more cathode-related processes dominating the self-discharge current and presumably improving the capacity retention due to electrolyte oxidation. Finally, the Na-Ion cells showed anode overhang equalization effects like Li-Ion cells.","PeriodicalId":17364,"journal":{"name":"Journal of The Electrochemical Society","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141926658","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-08DOI: 10.1149/1945-7111/ad6d01
Muhammad Miteeullah, U. Draz, Ammar Tariq, Rafia Nasir, Muhammad Irfan, S. Ramay, S. Atiq
The urge to transition from fossil fuels to sustainable energy solutions has driven the exploration of advanced energy conversion and storage technologies. In this context, supercapacitors have garnered substantial interest for their high cyclic life span and power density. This study presents the facile synthesis of NiO and NiO/rGO composites (NO-I, NO-II, and NO-III) for battery-type applications, with a focus on their structural, morphological, and electrochemical characterizations. The results indicate the successful fabrication of crystalline materials with notable porosity in NO-III. Electrochemical analysis reveals battery-type behavior, with an inverse relationship between specific capacity (Q) and scan rates. Galvanostatic charge-discharge (GCD) measurements highlight enhanced charge storage capability, particularly in NO-III. GCD results showed the maximum values for (Q = 288 Cg-1), energy density (E = 36.12 Wh/kg), and power density (P= 3.06 kW/h) at 1.7 Ag-1 for NO-III, underscoring its potential for advanced energy storage systems.
{"title":"Utilization of NiO-rGO Nanoarchitectures-Based Composite Electrodes for High-Performance Electrochemical Applications","authors":"Muhammad Miteeullah, U. Draz, Ammar Tariq, Rafia Nasir, Muhammad Irfan, S. Ramay, S. Atiq","doi":"10.1149/1945-7111/ad6d01","DOIUrl":"https://doi.org/10.1149/1945-7111/ad6d01","url":null,"abstract":"\u0000 The urge to transition from fossil fuels to sustainable energy solutions has driven the exploration of advanced energy conversion and storage technologies. In this context, supercapacitors have garnered substantial interest for their high cyclic life span and power density. This study presents the facile synthesis of NiO and NiO/rGO composites (NO-I, NO-II, and NO-III) for battery-type applications, with a focus on their structural, morphological, and electrochemical characterizations. The results indicate the successful fabrication of crystalline materials with notable porosity in NO-III. Electrochemical analysis reveals battery-type behavior, with an inverse relationship between specific capacity (Q) and scan rates. Galvanostatic charge-discharge (GCD) measurements highlight enhanced charge storage capability, particularly in NO-III. GCD results showed the maximum values for (Q = 288 Cg-1), energy density (E = 36.12 Wh/kg), and power density (P= 3.06 kW/h) at 1.7 Ag-1 for NO-III, underscoring its potential for advanced energy storage systems.","PeriodicalId":17364,"journal":{"name":"Journal of The Electrochemical Society","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141927465","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-08DOI: 10.1149/1945-7111/ad6cfe
Debashish Chakraborty, Raghvendra Gupta, Amit Gupta
The risk of thermal runaway (TR) in high-energy-density Lithium-ion batteries (LIBs), which may initiate at around 90℃, is a critical safety concern, particularly in regions where summer temperatures can reach nearly 50℃. While multiple exothermic reactions that cause TR and modeled using Arrhenius equations lead to good predictions in controlled oven tests, their use in practical applications is questionable as these do not consider internal electrochemical processes that cause temperature rise and trigger exothermic reactions. Further, limited literature focuses on coupling electrochemical thermal models with exothermic reactions. This study demonstrates a method to couple the electrochemical and thermal runaway models for a commercial cylindrical Lithium-ion cell. The proposed model averages pseudo-2D electrochemical heat and couples it to a two-dimensional, axisymmetric heat transfer model of 18650-type Lithium-ion cell. The jellyroll structure is approximated as a homogeneous and anisotropic domain for electrochemical and exothermic heating. Simulations are performed through several, uninterrupted charge-discharge cycles at different ambient temperatures and C-rates. We show that while cycling rate is critical in instigating and accelerating TR, parameters like ambient temperature, particle radii and initial electrolyte concentration also play a role in determining the core temperature and its rate of growth in the cell.
{"title":"Coupled Electrochemical-Thermal Runaway Model of Lithium-Ion Cells Operating Under High Ambient Temperatures","authors":"Debashish Chakraborty, Raghvendra Gupta, Amit Gupta","doi":"10.1149/1945-7111/ad6cfe","DOIUrl":"https://doi.org/10.1149/1945-7111/ad6cfe","url":null,"abstract":"\u0000 The risk of thermal runaway (TR) in high-energy-density Lithium-ion batteries (LIBs), which may initiate at around 90℃, is a critical safety concern, particularly in regions where summer temperatures can reach nearly 50℃. While multiple exothermic reactions that cause TR and modeled using Arrhenius equations lead to good predictions in controlled oven tests, their use in practical applications is questionable as these do not consider internal electrochemical processes that cause temperature rise and trigger exothermic reactions. Further, limited literature focuses on coupling electrochemical thermal models with exothermic reactions. This study demonstrates a method to couple the electrochemical and thermal runaway models for a commercial cylindrical Lithium-ion cell. The proposed model averages pseudo-2D electrochemical heat and couples it to a two-dimensional, axisymmetric heat transfer model of 18650-type Lithium-ion cell. The jellyroll structure is approximated as a homogeneous and anisotropic domain for electrochemical and exothermic heating. Simulations are performed through several, uninterrupted charge-discharge cycles at different ambient temperatures and C-rates. We show that while cycling rate is critical in instigating and accelerating TR, parameters like ambient temperature, particle radii and initial electrolyte concentration also play a role in determining the core temperature and its rate of growth in the cell.","PeriodicalId":17364,"journal":{"name":"Journal of The Electrochemical Society","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141928121","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-08DOI: 10.1149/1945-7111/ad6cbd
E. Zsoldos, Daphne Thompson, William Black, Saad Azam, Jeff R. Dahn
Lithium iron phosphate (LFP) battery cells are ubiquitous in electric vehicles and stationary energy storage because they are cheap and have a long lifetime. This work compares LFP/graphite pouch cells undergoing charge-discharge cycles over five state of charge (SOC) windows (0 – 25%, 0- 60%, 0 – 80%, 0 – 100%, and 75 – 100%). Cycling LFP cells across a lower average SOC results in less capacity fade than cycling across a higher average SOC, regardless of depth of discharge. The primary capacity fade mechanism is lithium inventory loss due to: lithiated graphite reactivity with electrolyte, which increases incrementally with SOC, and lithium alkoxide species causing iron dissolution and deposition on the negative electrode at high SOC which further accelerates lithium inventory loss. Our results show that even low voltage LFP systems (3.65 V) have a tradeoff between average SOC and lifetime. Operating LFP cells at lower average SOC can extend their lifetime substantially in both EV and grid storage applications.
{"title":"The Operation Window of Lithium Iron Phosphate / Graphite Cells Affects their Lifetime","authors":"E. Zsoldos, Daphne Thompson, William Black, Saad Azam, Jeff R. Dahn","doi":"10.1149/1945-7111/ad6cbd","DOIUrl":"https://doi.org/10.1149/1945-7111/ad6cbd","url":null,"abstract":"\u0000 Lithium iron phosphate (LFP) battery cells are ubiquitous in electric vehicles and stationary energy storage because they are cheap and have a long lifetime. This work compares LFP/graphite pouch cells undergoing charge-discharge cycles over five state of charge (SOC) windows (0 – 25%, 0- 60%, 0 – 80%, 0 – 100%, and 75 – 100%). Cycling LFP cells across a lower average SOC results in less capacity fade than cycling across a higher average SOC, regardless of depth of discharge. The primary capacity fade mechanism is lithium inventory loss due to: lithiated graphite reactivity with electrolyte, which increases incrementally with SOC, and lithium alkoxide species causing iron dissolution and deposition on the negative electrode at high SOC which further accelerates lithium inventory loss. Our results show that even low voltage LFP systems (3.65 V) have a tradeoff between average SOC and lifetime. Operating LFP cells at lower average SOC can extend their lifetime substantially in both EV and grid storage applications.","PeriodicalId":17364,"journal":{"name":"Journal of The Electrochemical Society","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141927042","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-08DOI: 10.1149/1945-7111/ad68e4
Macgregor F. Macintosh, Mohsen Shakouri and M. N. Obrovac
Substitutional Li[Ni0.6Mn0.2Co0.2]O2 oxides (known as NMC622) were made by all-dry synthesis with Fe and Ti substituting Co and Mn, respectively. The substitutions were performed in three series, Fe substitution for Co, Ti substitution for Mn, and Fe and Ti co-substitution for Co and Mn, according to the formula Li(Ni0.6Mn0.2−yCo0.2−xFexTiy)O2. The resulting oxides were evaluated as cathode materials for Li-ion batteries. Fe-substitution for Co resulted in increased intersite mixing, resulting in increased polarization and capacity fade. Ti-substitution for Mn also resulted in increased intersite mixing, but the mixing was due to Ti3+ in the Li-layer. As a result, Ti-substituted NMCs had improved capacity retention and reduced polarization. These effects were independent of each other, so that Ti could partially offset the negative aspects of Fe-substitution. Additionally, layered Mn-free Li(Ni0.6Ti0.2Co0.2)O2 (NTC622) was produced as an endmember of this series for the first time with low intersite mixing and superior electrochemical performance in comparison to previous reports. These results demonstrate benefits of all-dry Ti-substitution in NMC and the all-dry synthesis method as an avenue towards new cathode composition discovery.
用全干法合成法制备了取代型 Li[Ni0.6Mn0.2Co0.2]O2 氧化物（又称 NMC622），其中 Fe 和 Ti 分别取代了 Co 和 Mn。按照 Li（Ni0.6Mn0.2-yCo0.2-xFexTiy）O2 的公式，分别用 Fe 替代 Co、Ti 替代 Mn 以及 Fe 和 Ti 共同替代 Co 和 Mn 三个系列进行了替代。所得氧化物被评估为锂离子电池的阴极材料。用 Fe 替代 Co 增加了位点间的混合，从而增加了极化和容量衰减。用钛代替锰也会导致晶间混合增加，但这种混合是由于锂层中的 Ti3+ 造成的。因此，以钛替代锰的 NMC 提高了容量保持率并降低了极化。这些影响是相互独立的，因此钛可以部分抵消铁取代的负面影响。此外，作为该系列的末端成员，首次制备出了层状无锰 Li（Ni0.6Ti0.2Co0.2）O2（NTC622），与之前的报告相比，它具有较低的位间混合和优异的电化学性能。这些结果表明了全干法钛替代在 NMC 中的优势，以及全干法合成方法是发现新阴极成分的一种途径。
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Pub Date : 2024-08-07DOI: 10.1149/1945-7111/ad6939
Rodney LaFollette and Michael D. Eskra
It is often observed that some runaway Li-ion cells with layered cathode materials become much hotter internally than existing thermal runaway models predict. Further, metals originally in the positive active material (such as Co, Ni, and Mn) are often found in cells whose temperatures became very high. It has been postulated that the formation of metals can be attributed to reduction of rock salt species (MO, where M is the metal), or the reaction of lithiated active material (LiMO2) with CO2. We propose an alternate process for formation of metals that also results in very high cell temperatures, namely thermite reactions between the Al positive electrode current collector and the positive active material. These reactions are highly exothermic, in contrast with the reactions of MO and LiMO2 mentioned. In this paper the thermodynamics of thermite reactions are presented. Incorporating thermite reactions in runaway models will likely improve temperature prediction of Li-ion cells in thermal runaway.
人们经常发现，一些采用层状阴极材料的失控锂离子电池的内部温度比现有热失控模型预测的温度要高得多。此外，在温度变得非常高的电池中，经常会发现原本存在于正极活性材料中的金属（如钴、镍和锰）。据推测，金属的形成可归因于岩盐物种（MO，其中 M 为金属）的还原，或锂化活性材料（LiMO2）与二氧化碳的反应。我们提出了另一种金属形成过程，它也会导致极高的电池温度，即铝正极集流器与正极活性材料之间的热反应。这些反应的放热程度很高，与上述 MO 和 LiMO2 反应形成鲜明对比。本文介绍了热释电反应的热力学。将热亚硝酸盐反应纳入失控模型可能会改善热失控锂离子电池的温度预测。
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Pub Date : 2024-08-07DOI: 10.1149/1945-7111/ad6938
Wolfgang G. Bessler
Capacity and internal resistance are key properties of batteries determining energy content and power capability. We present a novel algorithm for estimating the absolute values of capacity and internal resistance from voltage and current data. The algorithm is based on voltage-controlled models. Experimentally-measured voltage is used as an input variable to an equivalent circuit model. The simulation gives current as output, which is compared to the experimentally-measured current. We show that capacity loss and resistance increase lead to characteristic fingerprints in the current output of the simulation. In order to exploit these fingerprints, a theory is developed for calculating capacity and resistance from the difference between simulated and measured current. The findings are cast into an algorithm for operando diagnosis of batteries operated with arbitrary load profiles. The algorithm is demonstrated using cycling data from lithium-ion pouch cells operated on full cycles, shallow cycles, and dynamic cycles typical for electric vehicles. Capacity and internal resistance of a “fresh” cell was estimated with high accuracy (mean absolute errors of 0.9% and 1.8%, respectively). For an “aged” cell, the algorithm required adaptation of the model’s open-circuit voltage curve to obtain high accuracies. Highlights Operando diagnosis of capacity and internal resistance of rechargeable batteries. Novel algorithm developed, validated and demonstrated. Use of voltage-controlled models: Voltage as input, current as output. High accuracy achieved for dynamic operation of an NMC-LMO/graphite pouch cell.
{"title":"Capacity and Resistance Diagnosis of Batteries with Voltage-Controlled Models","authors":"Wolfgang G. Bessler","doi":"10.1149/1945-7111/ad6938","DOIUrl":"https://doi.org/10.1149/1945-7111/ad6938","url":null,"abstract":"Capacity and internal resistance are key properties of batteries determining energy content and power capability. We present a novel algorithm for estimating the absolute values of capacity and internal resistance from voltage and current data. The algorithm is based on voltage-controlled models. Experimentally-measured voltage is used as an input variable to an equivalent circuit model. The simulation gives current as output, which is compared to the experimentally-measured current. We show that capacity loss and resistance increase lead to characteristic fingerprints in the current output of the simulation. In order to exploit these fingerprints, a theory is developed for calculating capacity and resistance from the difference between simulated and measured current. The findings are cast into an algorithm for operando diagnosis of batteries operated with arbitrary load profiles. The algorithm is demonstrated using cycling data from lithium-ion pouch cells operated on full cycles, shallow cycles, and dynamic cycles typical for electric vehicles. Capacity and internal resistance of a “fresh” cell was estimated with high accuracy (mean absolute errors of 0.9% and 1.8%, respectively). For an “aged” cell, the algorithm required adaptation of the model’s open-circuit voltage curve to obtain high accuracies. Highlights Operando diagnosis of capacity and internal resistance of rechargeable batteries. Novel algorithm developed, validated and demonstrated. Use of voltage-controlled models: Voltage as input, current as output. High accuracy achieved for dynamic operation of an NMC-LMO/graphite pouch cell.","PeriodicalId":17364,"journal":{"name":"Journal of The Electrochemical Society","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141942902","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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