Dynamic Li+ Capture through Ligand-Chain Interaction for the Regeneration of Depleted LiFePO4 Cathode.

After application in electric vehicles, spent LiFePO4 (LFP) batteries are typically decommissioned. Traditional recycling methods face economic and environmental constraints. Therefore, direct regeneration has emerged as a promising alternative. However, irreversible phase changes can significantly hinder the efficiency of the regeneration process owing to structural degradation. Moreover, improper storage and treatment practices can lead to metamorphism, further complicating the regeneration process. In this study, a sustainable recovery method is proposed for the electrochemical repair of LFP batteries. A ligand-chain Zn-complex (ZnDEA) is utilized as a structural regulator, with its ─NH─ group alternatingly facilitating the binding of preferential transition metal ions (Fe3+ during charging and Zn2+ during discharging). This dynamic coordination ability helps to modulate volume changes within the recovered LFP framework. Consequently, the recovered LFP framework can store more Li-ions, enhance phase transition reversibility between LFP and FePO4 (FP), modify the initial Coulombic efficiency, and reduce polarization voltage differences. The recovered LFP cells exhibit excellent capacity retention of 96.30% after 1500 cycles at 2 C. The ligand chain repair mechanism promotes structural evolution to facilitate ion migration, providing valuable insights into the targeted ion compensation for environmentally friendly recycling in practical applications.

Preoperative Evaluation of Malignant Perihilar Biliary Obstruction: Negative-Contrast CT Cholangiopancreatography and CT Angiography Versus MRCP and MR Angiography.

OBJECTIVE: The purpose of this study was to compare negative-contrast CT cholangiopancreatography (CTCP) and CT angiography (CTA) with MRCP and MR angiography (MRA) for the preoperative evaluation of malignant perihilar biliary obstruction. MATERIALS AND METHODS: Twenty-one patients with pathologically proven malignant perihilar biliary obstructions who had undergone both CT and MRI examinations were reviewed retrospectively. Two reviewers independently analyzed the two image sets-the negative-contrast CTCP and CTA images (i.e., CT set) and the MRCP and MRA images (i.e., MRI set)-in preoperatively evaluating the classification of malignant perihilar biliary obstruction, hepatic artery and portal vein invasion, nodal metastasis, and organ spread. The results were compared with surgical and pathologic records. RESULTS: For the classification of malignant perihilar biliary obstruction on the two image sets, the accuracy was not statistically significant (p = 1.000 for reviewer 1 and p = 0.500 for reviewer 2). For the evaluation of portal vein invasion, nodal metastasis, and organ spread, the accuracies were also not statistically significantly different (p = 0.335, 0.339, and 0.781 for reviewer 1; and p = 0.403, 0.495, and 0.325 for reviewer 2, respectively). In the assessment of hepatic artery status, the accuracy was statistically significant (p = 0.046 for reviewer 1 and p = 0.036 for reviewer 2). CONCLUSION: Compared with the MRI set, the CT set provides equivalent performance in assessing the classification of malignant perihilar biliary obstruction, portal vein involvement, nodal metastasis, and organ spread, but has higher accuracy in assessing arterial invasion.

Differentiation of noncalculous periampullary obstruction: comparison of CT with negative-contrast CT cholangiopancreatography versus MRI with MR cholangiopancreatography.

OBJECTIVES: The purpose of this study was to compare CT with negative-contrast CT cholangiopancreatography (nCTCP) using subvolume minimum intensity projection (MinIP) versus MRI with MRCP in differentiating noncalculous periampullary obstruction. METHODS: Sixty-four patients with clinically proven noncalculous periampullary obstructions who had undergone both MDCT and MR examinations before operation were reviewed retrospectively. Two reviewers independently interpreted the two image sets (the CT with nCTCP set [CT set] vs. the MRI with MRCP set [MRI set]) in differentiating both benign from malignant obstruction and pancreatic head carcinoma (PHC) from non-PHC, and the results were compared to the final clinical records. RESULTS: In this study, no statistically significant differences were observed in the accuracy of differentiating benign from malignant periampullary obstruction (p = 0.754 for reviewer 1 and p = 0.508 for reviewer 2) on the two image sets. The accuracy of differentiating PHC from non-PHC was also statistically insignificant (p = 0.125 for reviewer 1 and p = 1.000 for reviewer 2) on the two image sets. CONCLUSION: The CT set provides a comparable performance to that of the MRI set in differentiating noncalculous periampullary obstruction. KEY POINTS: • nCTCP with subvolume MinIP is a practical tool in evaluating biliary obstruction • Two image sets have a comparable performance in differentiating noncalculous periampullary obstruction • MDCT could serve as an alternative in patients not eligible for MRI.