An estimate of the amount of geological CO2 storage over the period 1996-2020

Existing centralised databases of industrial-scale CCS report various characteristics including capture capacities but do not specify the amount of CO2 stored from commercial CCS facilities. We review a variety of publicly available sources to estimate the amount of CO2 that has been captured and stored by operational CCS facilities since 1996. We organise these sources into three categories broadly corresponding to the associated degree of legal liability or auditing. Data were found for twenty commercial-scale facilities, indicating a combined capture capacity of 36 MtCO2 per year. Combining data from all three categories suggests that approximately 27 MtCO2 of this was stored in the subsurface in 2019. However, considering only categories 2 and 1 of reporting, storage estimates for 2019 reduce to 25 MtCO2 and 11 MtCO2, respectively. Nearly half of the projects investigated here are reporting injection rates close to their originally proposed capture rate capacity. Our data also show that between 1996 and 2020, 196 Mt of CO2 has been cumulatively stored, combining data for all three categories. The database presented here provides further insight into the factors influencing performances of CCS operations and the data can be used to parameterise energy system models for analysing plausible scaleup trajectories of CCS.

4G to 5G Network Evolution: Advantages and Differences

Starting from the emergence of 1st Generation network (1G), wireless mobile communications have been undergoing an evolution - from 2nd Generation (2G), 3rd Generation (3G), 4th Generation (4G) networks to 5th Generation network (5G) at present. The fifth era is only a continuation of the ongoing evolution as it is still in the research phase and is also the basis for further development of industries and the society in general. The paper presents and compares the fourth and fifth generation of wireless mobile communications, focusing on the differences and progress in terms of data transmission rate, capacity, architecture, technology and applied multiple-technique approaches and services provided.

Rapid Gelling of Guar Gum Hydrogel Stabilized by Copper Hydroxide Nanoclusters for Efficient Removal of Heavy Metal and Supercapacitors

In this paper, guar gum (GG) hydrogel has been successfully prepared by adding GG and Cu2+ mixture into an alkaline medium. The formation mechanism of the hydrogel has been investigated through various techniques. Results reveal GG facilitates the formation of ultrafine copper hydroxide clusters with a diameter of ∼3 nm. Moreover, these nanoclusters bring about a rapid gelling of GG within 10 ms. The synthesized hydrogel is applied to the adsorption of heavy metal ions from wastewater. The hydrogel shows excellent removal efficiency in removing various heavy metal ions. Besides, the hydrogel derived porous carbon exhibits high specific capacitance (281 F/g at 1 A/g) and excellent rate capacity. The high contaminant removal efficiency character and excellent electrochemical performance endow GG hydrogel with potential applications in the environmental and energy storage field.

Hybrid Deep Eutectic Solvent of LiTFSI-Ethylene Glycol Organic Electrolyte for Activated Carbon-Based Supercapacitors

This research work demonstrates a novel hybrid electrolyte based on a deep eutectic solvent (DES) combined with organic solvents for high-performance supercapacitors. DES was formed between ethylene glycol (EG) and lithium bis((trifluoromethyl)sulfonyl) imide (LiTFSI) and diluted by ethylene carbonate (EC) or acetonitrile (AN) with different amounts (10–50% wt.). Such a combination gives superior properties for hybrid electrolytes compared to pure DESs and reduces the volatility of mixed organic solvents. Regarding the electrochemical properties, DES-AN mixtures exhibited a better performance under high applied voltage and more reversible behavior than DES-EC ones, which suffered from the increasing distance in the electrical double layer. DES 1 : 4 + 20% wt. AN exhibited favorable electrolyte properties such as high ionic conductivity (3.1 mS·cm−1 at 30oC), relatively lower viscosity (14.28 mPa s at 30oC, approximately 2 times lower thanDES pure), and quite large electrochemical stability window up to 3.4 V (at 20–30% wt. AN) compared to the baseline electrolyte (LiTFSI/TBABF4 in AN). With these interesting properties, selected hybrid electrolyte (DES 1 : 4 + 20% wt. AN) tested in the symmetric capacitor using the activated carbon offered decent capacitance (15 F·g−1 at 3.4 V with a scanning rate of 1 A·g−1 and remains around 95% after 100 cycles) and good charge-discharge durability (>80% retention after 2000 cycles), especially the EDLC with DES 1 : 4 + 20% wt. AN shows good rate capacity (13.2 F·g−1 at 2 A·g−1, remaining 6 F·g−1 at 10 A·g−1).

All-Climate Aluminum-Ion Batteries Based on Binder-Free MOF-Derived FeS2@C/CNT Cathode

Aluminum-ion batteries (AIBs) are promising next-generation batteries systems because of their features of low cost and abundant aluminum resource. However, the inferior rate capacity and poor all-climate performance, especially the decayed capacity under low temperature, are still critical challenges toward high-specific-capacity AIBs. Herein, we report a binder-free and freestanding metal–organic framework-derived FeS2@C/carbon nanotube (FeS2@C/CNT) as a novel all-climate cathode in AIBs working under a wide temperature window between −25 and 50 °C with exceptional flexibility. The resultant cathode not only drastically suppresses the side reaction and volumetric expansion with high capacity and long-term stability but also greatly enhances the kinetic process in AIBs with remarkable rate capacity (above 151 mAh g−1 at 2 A g−1) at room temperature. More importantly, to break the bottleneck of the inherently low capacity in graphitic material-based all-climate AIBs, the new hierarchical conductive composite FeS2@C/CNT highly promotes the all-climate performance and delivers as high as 117 mAh g−1 capacity even under −25 °C. The well-designed metal sulfide electrode with remarkable performance paves a new way toward all-climate and flexible AIBs.