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"Huggins, Robert"
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A high-rate and long cycle life aqueous electrolyte battery for grid-scale energy storage
New types of energy storage are needed in conjunction with the deployment of solar, wind and other volatile renewable energy sources and their integration with the electric grid. No existing energy storage technology can economically provide the power, cycle life and energy efficiency needed to respond to the costly short-term transients that arise from renewables and other aspects of grid operation. Here we demonstrate a new type of safe, fast, inexpensive, long-life aqueous electrolyte battery, which relies on the insertion of potassium ions into a copper hexacyanoferrate cathode and a novel activated carbon/polypyrrole hybrid anode. The cathode reacts rapidly with very little hysteresis. The hybrid anode uses an electrochemically active additive to tune its potential. This high-rate, high-efficiency cell has a 95% round-trip energy efficiency when cycled at a 5C rate, and a 79% energy efficiency at 50C. It also has zero-capacity loss after 1,000 deep-discharge cycles.
The integration of volatile renewable energy sources into the electrical power grid will require a significant increase in electrical storage capacity. Here a new type of safe, fast, inexpensive and long-life aqueous electrolyte battery is reported, which may aid the development of increased grid capacity.
Journal Article
Copper hexacyanoferrate battery electrodes with long cycle life and high power
Short-term transients, including those related to wind and solar sources, present challenges to the electrical grid. Stationary energy storage systems that can operate for many cycles, at high power, with high round-trip energy efficiency, and at low cost are required. Existing energy storage technologies cannot satisfy these requirements. Here we show that crystalline nanoparticles of copper hexacyanoferrate, which has an ultra-low strain open framework structure, can be operated as a battery electrode in inexpensive aqueous electrolytes. After 40,000 deep discharge cycles at a 17 C rate, 83% of the original capacity of copper hexacyanoferrate is retained. Even at a very high cycling rate of 83 C, two thirds of its maximum discharge capacity is observed. At modest current densities, round-trip energy efficiencies of 99% can be achieved. The low-cost, scalable, room-temperature co-precipitation synthesis and excellent electrode performance of copper hexacyanoferrate make it attractive for large-scale energy storage systems.
Batteries that operate at high power and cycling efficiencies could facilitate the development of large-scale energy storage systems. Wessells
et al.
report a metal–organic framework electrode that operates in an inexpensive aqueous electrolyte with excellent capacity retention over a very large number of cycles.
Journal Article
Network structure and regional innovation
The emergence of the network paradigm has led to growing interest in understanding network structures relating to knowledge flows and patterns of regional innovation. This paper explores the structure of knowledge networks stemming from ties between universities and other actors, principally firms. Based upon a network analysis of empirical data for regions across the UK, it is found that the most innovative and economically developed regions are more likely to be the location for actors holding highly central and influential positions within knowledge network architectures. It is concluded that network structures, and resulting stocks of structural network capital, influence patterns of regional innovation and development.
Journal Article
High-performance lithium battery anodes using silicon nanowires
There is great interest in developing rechargeable lithium batteries with higher energy capacity and longer cycle life for applications in portable electronic devices, electric vehicles and implantable medical devices
1
. Silicon is an attractive anode material for lithium batteries because it has a low discharge potential and the highest known theoretical charge capacity (4,200 mAh g
−1
; ref.
2
). Although this is more than ten times higher than existing graphite anodes and much larger than various nitride and oxide materials
3
,
4
, silicon anodes have limited applications
5
because silicon's volume changes by 400% upon insertion and extraction of lithium which results in pulverization and capacity fading
2
. Here, we show that silicon nanowire battery electrodes circumvent these issues as they can accommodate large strain without pulverization, provide good electronic contact and conduction, and display short lithium insertion distances. We achieved the theoretical charge capacity for silicon anodes and maintained a discharge capacity close to 75% of this maximum, with little fading during cycling.
Journal Article
Full open-framework batteries for stationary energy storage
New types of energy storage are needed in conjunction with the deployment of renewable energy sources and their integration with the electrical grid. We have recently introduced a family of cathodes involving the reversible insertion of cations into materials with the Prussian Blue open-framework crystal structure. Here we report a newly developed manganese hexacyanomanganate open-framework anode that has the same crystal structure. By combining it with the previously reported copper hexacyanoferrate cathode we demonstrate a safe, fast, inexpensive, long-cycle life aqueous electrolyte battery, which involves the insertion of sodium ions. This high rate, high efficiency cell shows a 96.7% round trip energy efficiency when cycled at a 5C rate and an 84.2% energy efficiency at a 50C rate. There is no measurable capacity loss after 1,000 deep-discharge cycles. Bulk quantities of the electrode materials can be produced by a room temperature chemical synthesis from earth-abundant precursors.
Battery technologies are promising for grid-scale applications, but existing batteries in general operate at low rates, have limited cycle life and are expensive. Pasta
et al
. develop a grid-scale battery based on Prussian Blue electrodes, which shows potential in overcoming these problems.
Journal Article
Socioeconomic factors and outcomes from exercise-related sudden cardiac arrest in high school student-athletes in the USA
ObjectiveMinority student-athletes have a lower survival rate from sudden cardiac arrest (SCA) than non-minority student-athletes. This study examined the relationship between high school indicators of socioeconomic status (SES) and survival in student-athletes with exercise-related SCA.MethodsHigh school student-athletes in the USA with exercise-related SCA on school campuses were prospectively identified from 1 July 2014 to 30 June 2018 by the National Center for Catastrophic Sports Injury Research. High school indicators of SES included the following: median household and family income, proportion of students on free/reduced lunch and percent minority students. Resuscitation details included witnessed arrest, presence of an athletic trainer, bystander cardiopulmonary resuscitation and use of an on-site automated external defibrillator (AED). The primary outcome was survival to hospital discharge. Differences in survival were analysed using risk ratios (RR) and univariate general log-binomial regression models.ResultsOf 111 cases identified (mean age 15.8 years, 88% male, 49% white non-Hispanic), 75 (68%) survived. Minority student-athletes had a lower survival rate compared with white non-Hispanic student-athletes (51.1% vs 75.9%; RR 0.67, 95% CI 0.49 to 0.92). A non-significant monotonic increase in survival was observed with increasing median household or family income and with decreasing percent minority students or proportion on free/reduced lunch. The survival rate was 83% if an athletic trainer was on-site at the time of SCA and 85% if an on-site AED was used.ConclusionsMinority student-athletes with exercise-related SCA on high school campuses have lower survival rates than white non-Hispanic athletes, but this difference is not fully explained by SES markers of the school.
Journal Article
Exertional Heat Stroke Survival at the Falmouth Road Race: 180 New Cases With Expanded Analysis
A high number of exertional heat stroke (EHS) cases occur during the Falmouth Road Race.
To extend previous analyses of EHS cases during the Falmouth Road Race by assessing or describing (1) EHS and heat exhaustion (HE) incidence rates, (2) EHS outcomes as they relate to survival, (3) the effect of the environment on these outcomes, and (4) how this influences medical provider planning and preparedness.
Descriptive epidemiologic study.
Falmouth Road Race.
Patients with EHS or HE admitted to the medical tent.
We obtained 8 years (2012 to 2019) of Falmouth Road Race anonymous EHS and HE medical records. Meteorologic data were collected and analyzed to evaluate the effect of environmental conditions on the heat illness incidence (exertional heat illness [EHI] = EHS + HE). The EHS treatment and outcomes (ie, cooling time, survival, and discharge outcome), number of HE patients, and wet bulb globe temperature (WBGT) for each race were analyzed.
A total of 180 EHS and 239 HE cases were identified. Overall incidence rates per 1000 participants were 2.07 for EHS and 2.76 for HE. The EHI incidence rate was 4.83 per 1000 participants. Of the 180 EHS cases, 100% survived, and 20% were transported to the emergency department. The WBGT was strongly correlated with the incidence of both EHS (r2 = 0.904, P = .026) and EHI (r2 = 0.912, P = .023).
This is the second-largest civilian database of EHS cases reported. When combined with the previous dataset of EHS survivors from this race, it amounts to 454 EHS cases resulting in 100% survival. The WBGT remained a strong predictor of EHS and EHI cases. These findings support 100% survival from EHS when patients over a wide range of ages and sexes are treated with cold-water immersion.
Journal Article
Practical Hydration Solutions for Sports
Personalized hydration strategies play a key role in optimizing the performance and safety of athletes during sporting activities. Clinicians should be aware of the many physiological, behavioral, logistical and psychological issues that determine both the athlete’s fluid needs during sport and his/her opportunity to address them; these are often specific to the environment, the event and the individual athlete. In this paper we address the major considerations for assessing hydration status in athletes and practical solutions to overcome obstacles of a given sport. Based on these solutions, practitioners can better advise athletes to develop practices that optimize hydration for their sports.
Journal Article
Entrepreneurship, innovation and regional growth: a network theory
Despite the growing acknowledgement that entrepreneurship is an important driver of regional innovation and growth, the role of the networks in these processes has been less formally examined. In order to address this gap, this paper proposes that the relationship between entrepreneurship, innovation and regional growth is governed by a series of network dynamics. Drawing upon aspects of endogenous growth theory and the knowledge spillover theory of entrepreneurship, it is proposed that the nature of the networks formed by entrepreneurial firms is a key determinant of regional growth differentials. In particular, network capital, in the form of investments in strategic relations to gain access to knowledge, is considered to mediate the relationship between entrepreneurship and innovation-based regional growth. It is suggested that network dynamics should be further incorporated into theories concerning the link between knowledge spillovers, entrepreneurship and regional growth. The paper concludes with a series of theoretical, entrepreneurial and policy implications emerging from the study.
Journal Article