Fabrication electro-spun Poly(vinyl alcohol)-Melamine nonwoven membrane composite separator for high-power lithium-ion batteries.

Current commercial separators used in lithium-ion batteries have inherent flaws, especially poor thermal stability, which pose substantial safety risks. This study introduces a high-safety composite membrane made from electrospun poly(vinyl alcohol)-melamine (PVAM) and polyvinylidene fluoride (PVDF) polymer solutions via a dip coating method, designed for high-voltage battery systems. The poly(vinyl alcohol) and melamine components enhance battery safety, while the PVDF coating improves lithium-ion conductivity. The dip-coated PVDF/Esp-PVAM composite separators were evaluated for electrolyte uptake, contact angle, thermal stability, porosity, electrochemical stability and ionic conductivity. Notably, our Dip 1 % PVDF@Esp-PVAM composite separator exhibited excellent wettability and a lithium-ion conductivity of approximately 7.75 × 10⁻4 S cm⁻1 at room temperature. These separators outperformed conventional PE separators in half-cells with Ni-rich NCM811 cathodes, showing exceptional cycling stability with 93.4 % capacity retention after 100 cycles at 1C/1C, as compared to 84.8 % for PE separators. Our Dip 1 % PVDF@Esp-PVAM composite separator demonstrates significant potential for enhancing the long-term durability and high-rate performance of lithium-ion batteries, making it a promising option for long-term energy storage applications.

Unveiling high-power and high-safety lithium-ion battery separator based on interlayer of ZIF-67/cellulose nanofiber with electrospun poly(vinyl alcohol)/melamine nonwoven membranes.

Due to the poor thermal stability of conventional separators, lithium-ion batteries require a suitable separator to maintain system safety for long-term cycling performance. It must have high porosity, superior electrolyte uptake ability, and good ion-conducting properties even at high temperatures. In this work, we demonstrate a novel composite membrane based on sandwiching of zeolitic imidazole frameworks-67 decorated cellulose acetate nanofibers (ZIF-67@CA) with electrospun poly(vinyl alcohol)/melamine (denoted as PVAM) nonwoven membranes. The as-prepared sandwich-type membranes are called PVAM/x%ZIF-67@CA/PVAM. The middle layer of composite membranes is primarily filled with different weight percentages of ZIF-67 nanoparticles (x = 5, 15, and 25 wt%), which both reduces the non-uniform porous structure of CA and increases its thermal stability. Therefore, our sandwich-type PVAM/x%ZIF-67@CA/PVAM membrane exhibits a higher thermal shrinkage effect at 200 °C than the commercial polyethylene (PE) separator. Due to its high electrolyte uptake (646.8%) and porosity (85.2%), PVAM/15%ZIF-67@CA/PVAM membrane achieved high ionic conductivity of 1.46 × 10-3 S cm-1 at 70 °C, as compared to the commercial PE separator (ca. 6.01 × 10-4 S cm-1 at 70 °C). Besides, the cell with PVAM/15%ZIF-67@CA/PVAM membrane shows an excellent discharge capacity of about 167.5 mAh g-1after 100 cycles at a 1C rate with a capacity retention of 90.3%. The ZIF-67 fillers in our sandwich-type composite membrane strongly attract anions (PF6-) through Lewis' acid-base interaction, allowing uniform Li+ ion transport and suppressing Li dendrites. As a result, we found that the PVAM/15%ZIF-67@CA/PVAM composite nonwoven membrane is applicable to high-power, high-safety lithium-ion battery systems that can be used in electric vehicles (EVs).

[Progress in arthroscopic surgery for injury of superior labrum anterior posterior of shoulder joint].

Superior labrum anterior posterior (SLAP) injury is a major challenge for orthopedic surgeons, due to the poor healing ability of the injured labrum. Although arthroscopic surgery is the gold standard for the treatment of SLAP injury, there are still disputes about the adaptation of different surgical techniques, the choice of anchors during operation, knotted or knotless anchors, and fixation methods. The authors believe that arthroscopic repair of SLAP lesions is effective for young patients with intact glenoid labrum(<35 years old) or with extensive activity, where single and knotless anchor is preferred. For the older patients(≥35 years old) with degeneration and wear of glenoid labrum, biceps tenodesis is more preferable, and interference screw fixation technique is recommended. As for patients with failed SLAP repair, biceps tenodesis can achieve a high success rate as a revision surgery. By review of the relevant literature in recent years, this paper summarizes the adaptation of different surgical methods of arthroscopic treatment of SLAP injury, intraoperative anchoring techniques, fixation methods and other improved surgical techniques.

[Arthroscopic subscapularis augmentation for the treatment of recurrent dislocation of shoulder with severe glenoid injury].

OBJECTIVE: To investigate the method and clinical effects of the treatment of recurrent shoulder dislocation with severe glenoid injury by arthroscopic subscapularis augmentation. METHODS: From March 2019 to August 2020, 16 patients with recurrent dislocation of shoulder with severe glenoid injury underwent arthroscopic subscapularis augmentation, including 10 males and 6 females, aged from 18 to 50 years old with an average of (29.06±10.54) years old, 4 cases of left shoulder and 12 cases of right shoulder.Visual analogue scale (VAS), American Shoulder and Elbow Surgeons (ASES) score and Rowe score were used to evaluate shoulder function and stability before and after operation. RESULTS: All the 16 patients were followed up from 12 to 29 months, with an average of (18.75±7.26) months. VAS score decreased from 5.25±1.13 before operation to 1.37±0.65 at the final follow-up;ASES score increased from 59.44±9.93 before surgery to 90.88±4.00 at the final follow-up; Rowe score of shoulder increased from 51.56±8.89 before surgery to 92.19±7.06 at the final follow-up, and the differences were statistically significant (P<0.05). No dislocation was observed during follow-up. No clinical complications such as incision infection, vascular and nerve injury occurred in all patients after operation. CONCLUSION: Arthroscopic subscapularis augmentation in the treatment of recurrent dislocation of shoulder with severe glenoid injury is satisfactory. It is an effective treatment method of recurrent dislocation of shoulder joint with severe glenoid injury, and external rotation function in patients with almost unaffected.

[Comparative study on arthroscopic double posterior medial approach versus open surgery for acute simple posterior cruciate ligament tibial avulsion fracture].

OBJECTIVE: To compare difference in clnical efficacy between arthroscopic double posterior internal approach and incisional surgery for acute simple posterior cruciate ligament tibial avulsion fractures. METHODS: Totally 52 patients with acute simple posterior cruciate ligament tibial avulsion fractures treated from June 2016 to June 2020 were retrospectively analyzed and divided into two groups according to different surgical protocols, 27 patients in arthroscopic group were treated with arthroscopic double posterior internal approach, including 16 males and 11 females, aged from 19 to 52 years old, with an average age of (34.9±9.2) years old;25 patients in open reduction group were treated with posterior medial knee incision, including 14 males and 11 females, aged from 18 to 54 years old , with an average age of(33.7±8.4) years old. Operation time, incision length, intraoperative bleeding, hospitalization days, hospitalization cost, fracture healing, complications, postoperative Lysholm score and IKDC score at 12 months were observed and compared between two groups. RESULTS: All patients in both groups were completed opertaion successfully without vascular or nerve injury, and 52 patients were followed up from 6 to 24 months with an average of (15.0±1.7) months. Operation time and hospitalization cost in arthroscopic group were significantly greater than those in open reduction group(P<0.05);intraoperative bleeding, incision length, and hospitalization days in arthroscopic group were less than those in open reduction group(P<0.05);preoperative Lysholm score in arthroscopic group and open reduction group were 49.1±2.3 and 48.9±1.1 respectively, and improved to 95.9±1.7 and 86.4±1.2 at 12 months after operation respectively(P<0.05);preoperative IKDC scores in arthroscopic group and open reduction group were 47.6±4.1 and 48.1±3.9 respectively, and improved to 96.9±1.5 and 87.1±1.4 at 12 months after operation(P<0.05). CONCLUSION: Arthroscopic double posterior internal approach for acute simple posterior cruciate ligament tibial stop avulsion fracture has satisfactory early results and better efficacy than traditional open surgery, which has advantages of less trauma, faster recovery and easier operation.

[Early efficacy analysis on arthroscopic autologous osteochondral grafting in the treatment of recurrent anterior shoulder dislocation].

OBJECTIVE: To investigate the early efficacy of arthroscopic autologous osteochondral grafting in the treatment of recurrent anterior shoulder dislocation. METHODS: From January 2019 to January 2021, 17 patients with recurrent anterior dislocation of shoulder who underwent arthroscopic autologous osteochondral grafting were selected, including 12 males and 5 females, ranging in age from 17 to 55 years old, with a mean of (32.88±12.33) years old. Rowes rating system for Bankart repair(Rowe), Oxford Shoulder Instability Score (OSIS) and Simple Shoulder Test (SST) were compared before operation, 6 months after operation and at the latest follow-up. OSIS and SST used to evaluate shoulder function were recorded before surgery and at the latest follow-up. The shoulder mobility and intraoperative and postoperative complications were also recorded. RESULTS: All 17 patients were followed up, and the duration ranged from 7 to 25 months, with a mean of (18.4±5.4) months. During the follow-up period, there was no re-dislocation, no vascular or nerve injury. Rowe score increased from 26.2±6.0 before operation to 74.4±4.0 and 82.4±3.1 after 6 months and the latest follow-up. There was significant difference in Rowe score between different time points after operation and before operation (P<0.05). The OSIS increased from 37.0±3.6 before operation to 47.4±2.6 and 52.7±2.6 after 6 months and the latest follow-up. There was significant difference in OSIS between different time points after operation and before operation (P<0.05). The SST score increased from 6.8±0.7 before operation to 9.8±0.8, 11.6±2.6 after 6 months and the latest follow-up. There was significant difference in SST score between different time points after operation and before operation (P<0.05). At the latest follow-up, the lateral external rotation and abduction external rotation activities of the patient were significantly improved compared with those before operation. CONCLUSION: This study provides preliminary evidence that arthroscopic autologous osteochondral grafting can achieve satisfactory early clinical outcomes and stability in patients with recurrent anterior shoulder dislocation with glenoid fracture and defect less than <20%, which is a reliable and effective procedure.