Nonintrusive thermal-wave sensor for operando quantification of degradation in commercial batteries.

Monitoring real-world battery degradation is crucial for the widespread application of batteries in different scenarios. However, acquiring quantitative degradation information in operating commercial cells is challenging due to the complex, embedded, and/or qualitative nature of most existing sensing techniques. This process is essentially limited by the type of signals used for detection. Here, we report the use of effective battery thermal conductivity (keff) as a quantitative indicator of battery degradation by leveraging the strong dependence of keff on battery-structure changes. A measurement scheme based on attachable thermal-wave sensors is developed for non-embedded detection and quantitative assessment. A proof-of-concept study of battery degradation during fast charging demonstrates that the amount of lithium plating and electrolyte consumption associated with the side reactions on the graphite anode and deposited lithium can be quantitatively distinguished using our method. Therefore, this work opens the door to the quantitative evaluation of battery degradation using simple non-embedded thermal-wave sensors.

Extreme fast charging of commercial Li-ion batteries via combined thermal switching and self-heating approaches.

The mass adoption of electric vehicles is hindered by the inadequate extreme fast charging (XFC) performance (i.e., less than 15 min charging time to reach 80% state of charge) of commercial high-specific-energy (i.e., >200 Wh/kg) lithium-ion batteries (LIBs). Here, to enable the XFC of commercial LIBs, we propose the regulation of the battery's self-generated heat via active thermal switching. We demonstrate that retaining the heat during XFC with the switch OFF boosts the cell's kinetics while dissipating the heat after XFC with the switch ON reduces detrimental reactions in the battery. Without modifying cell materials or structures, the proposed XFC approach enables reliable battery operation by applying <15 min of charge and 1 h of discharge. These results are almost identical regarding operativity for the same battery type tested applying a 1 h of charge and 1 h of discharge, thus, meeting the XFC targets set by the United States Department of Energy. Finally, we also demonstrate the feasibility of integrating the XFC approach in a commercial battery thermal management system.

Unraveling Li growth kinetics in solid electrolytes due to electron beam charging.

Revealing the local structure of solid electrolytes (SEs) with electron microscopy is critical for the fundamental understanding of the performance of solid-state batteries (SSBs). However, the intrinsic structural information in the SSB can be misleading if the sample's interactions with the electron beams are not fully understood. In this work, we systematically investigate the effect of electron beams on Al-doped lithium lanthanum zirconium oxide (LLZO) under different imaging conditions. Li metal is observed to grow directly on the clean surface of LLZO. The Li metal growth kinetics and the morphology obtained are found to be heavily influenced by the temperature, accelerating voltage, and electron beam intensity. We prove that the lithium growth is due to the LLZO delithiation activated by a positive charging effect under electron beam emission. Our results deepen the understanding of the electron beam impact on SEs and provide guidance for battery material characterization using electron microscopy.

Using Thermal Interface Resistance for Noninvasive Operando Mapping of Buried Interfacial Lithium Morphology in Solid-State Batteries.

The lithium metal-solid-state electrolyte interface plays a critical role in the performance of solid-state batteries. However, operando characterization of the buried interface morphology in solid-state cells is particularly difficult because of the lack of direct optical access. Destructive techniques that require isolating the interface inadvertently modify the interface and cannot be used for operando monitoring. In this work, we introduce the concept of thermal wave sensing using modified 3ω sensors that are attached to the outside of the lithium metal-solid-state cells to noninvasively probe the morphology of the lithium metal-electrolyte interface. We show that the thermal interface resistance measured by the 3ω sensors relates directly to the physical morphology of the interface and demonstrates that 3ω thermal wave sensing can be used for noninvasive operando monitoring the morphology evolution of the lithium metal-solid-state electrolyte interface.

All-Iron Redox Flow Battery Tailored for Off-Grid Portable Applications.

An all-iron redox flow battery is proposed and developed for end users without access to an electricity grid. The concept is a low-cost battery which the user assembles, discharges, and then disposes of the active materials. The design goals are: (1) minimize upfront cost, (2) maximize discharge energy, and (3) utilize non-toxic and environmentally benign materials. These are different goals than typically considered for electrochemical battery technology, which provides the opportunity for a novel solution. The selected materials are: low-carbon-steel negative electrode, paper separator, porous-carbon-paper positive electrode, and electrolyte solution containing 0.5 m Fe2 (SO4 )3 active material and 1.2 m NaCl supporting electrolyte. With these materials, an average power density around 20 mW cm(-2) and a maximum energy density of 11.5 Wh L(-1) are achieved. A simple cost model indicates the consumable materials cost US$6.45 per kWh(-1) , or only US$0.034 per mobile phone charge.

Outcome of nonoperative vs operative treatment of humeral shaft fractures: a retrospective study of 213 patients.

Standard treatment for most humeral shaft fractures is nonoperative functional bracing; however, certain clinical scenarios necessitate operative intervention. There have been few studies in the literature comparing nonoperative and operative fixation of humeral shaft fractures. Two-hundred thirteen adult patients with a humeral shaft fracture who satisfied inclusion criteria were treated at 2 level 1 trauma centers with either a functional brace (nonoperative treatment group) or compression plating (operative treatment group). Main outcome measures were evaluated retrospectively and included time to union, nonunion, malunion, infection, incidence of radial nerve palsy, and elbow range of motion (ROM). The occurrence of nonunion (20.6% vs 8.7%; P=.0128) and malunion (12.7% vs 1.3%; P=.0011) was statistically significant and more common in the nonoperative group. There was no significant difference in infection rate between nonoperative and operative treatment (3.2% vs 4.7%; P=1.0000). Radial nerve palsy presented after fracture treatment in 9.5% of patients in the nonoperative group and in 2.7% of patients managed operatively (P=.0678). No difference in time to union or ultimate ROM was found between the 2 groups. Closed treatment of humerus fractures had a significantly higher rate of nonunion and malunion while operative intervention demonstrated no significant differences in time to union, infection, or iatrogenic radial nerve palsy. Nonoperative management has historically been the treatment of choice for many humeral shaft fractures, however, in certain clinical scenarios these fractures may be well served by compression plating.

Results of femoral intramedullary nailing in patients who are obese versus those who are not obese: a prospective multicenter comparison study.

OBJECTIVES: Antegrade femoral nailing through a piriformis fossa starting point in patients who are obese has been demonstrated to be problematic. Retrograde femoral nailing therefore has been advocated in this patient population, but little data exist to support such a recommendation. The purpose of this study was to evaluate and compare antegrade and retrograde femoral nailing technique in both patients who are and are not obese. DESIGN: Prospective, multicenter, nonrandomized, internal review board (IRB)-approved study. SETTING: Four Level 1 trauma centers. PATIENTS: Patients (151) with a femoral shaft fracture (OTA 32) treated with intramedullary nailing were studied. Thirty-two with a body mass index (BMI) of >or=30 comprised the obese group (OG), and 119 with a BMI of <30 comprised the nonobese group (NOG). Antegrade nailing was performed in 15 patients from the OG and 84 from the NOG. Retrograde nailing was performed in 17 patients from the OG and 35 from the NOG. INTERVENTION: Reamed intramedullary nailing of a femoral shaft fracture. MAIN OUTCOME MEASURES: Patient and fracture characteristics, operative time, fluoroscopy time, healing, complications, and functional outcome based on the lower extremity measure (LEM) were evaluated. RESULTS: Antegrade technique in the OG was associated with a 52% greater average operative time (94 minutes) compared with antegrade nailing in the NOG (62 minutes; P < 0.003). For retrograde nailing technique, there was no difference in the average operative time between the OG (67 minutes) and NOG (62 minutes; P = 0.51). Antegrade technique in the OG was associated with a 79% greater average radiation exposure time (247 seconds) compared with antegrade nailing in the NOG (135 seconds; P < 0.03). For retrograde nailing technique, average fluoroscopy time was similar between the OG (76 seconds) and the NOG (63 seconds; P = 0.44). Within the OG, antegrade nailing required 40% greater average operative time (94 minutes versus 67 minutes, P < 0.02) and more than 3 times more average fluoroscopy time (242 seconds versus 76 seconds, P < 0.002) than retrograde nailing. Thirty-eight patients from the original cohort were not available for follow-up. Of the 113 patients followed (average 9 months, range: 4 to 25 months), healing complications occurred similarly between the 2 groups, with 1 nonunion and 2 delayed unions in the OG (12%), and 3 nonunions and 9 delayed unions in the NOG (14%). CONCLUSIONS: This study provides evidence, in the form of decreased operative and radiation exposure times, to support the use of retrograde nailing technique for the treatment of femoral shaft fractures in patients who are obese. Also, antegrade nailing was found to require significantly more operative and radiation exposure time in the patient who is obese as opposed to the patients who is not obese. Although having similar baseline functional scores, patients who are obese recovered at a slower rate and more incompletely than patients who are not obese.

A survey of orthopaedic traumatologists concerning the use of bone growth stimulators.

The purpose of the study was to determine the attitudes of members of the Orthopaedic Trauma Association (OTA) concerning the use and efficacy of bone growth stimulators. A questionnaire regarding bone growth stimulators was sent to the active members of the OTA. Descriptive statistics was performed using frequencies and percentages. All analyses were performed using Stata for Linux, version 8.0 (Intercooled Stata, Stata Corporation; College Station, TX). A response rate of 43% was obtained. Respondents indicated that they only occasionally used bone stimulators for the treatment of acute fractures and stress fractures. A majority of respondents have utilized stimulators for the treatment of delayed unions and nonunions. It was concluded that many members of the OTA utilize bone stimulators for delayed unions and nonunions, but not routinely for the treatment of acute fractures or stress fractures.

Hyperfine fields at the Li site in LiFePO(4)-type olivine materials for lithium rechargeable batteries: a (7)Li MAS NMR and SQUID study.

The (7)Li NMR isotropic shift for olivine LiMPO(4) (M = Fe, Mn, Co, Ni) is assigned to hyperfine coupling between the (7)Li nucleus and the transition metal unpaired electrons on the basis of the Curie-Weiss temperature dependence of the shift. The hyperfine shift arises from a linear combination of Li-O-M through-bond interactions wherein the unpaired A' electrons contribute a negative shift and the unpaired A' ' electrons contribute a positive shift. The hyperfine coupling constant is determined for each composition.