ADVANCED FUNCTIONAL MATERIALS
·
2021
·Vol. 32
·期 14
·2108267
·
IF 18.808
Ang Gao,Jiannian Xia,Min Li,Xia Lu,Feng Wang,Ru Yang
Crystal water mediated ion hydration and transport is a fundamental physicochemical process in a wide range of applications and natural processes, such as crystal water containing battery materials. In this context, K-Birnessite with interlaminar H 2 O (K 0.21 MnO 2 ⋅0.31H 2 O) is reported for nonaqueous potassium-ion storage with enhanced capacity and rate performance. It is clarified that the water–solid interface plays an important role in building and stabilizing the K-Birnessite layered structure and facilitating the K + diffusion for the K-ion battery system. In addition to the enlarged ionic channel dimensions and effective shielding of the electrostatic interaction with K + , the concerted diffusion of K + /H 2 O with the rotation of H 2 O molecules is further revealed to account for the quite low activation energies by first-principles simulations. Moreover, the interlayer H 2 O exerts on the electronic structures, and thus on the electrochemical voltage to result in the competition between the split of crystal field (“∇ JT ”) and the electronic superexchange interaction (“O w -K-O”) in the K-Birnessite structure. The results provide new insights into hydrated ion kinetics and open an exciting direction for battery material design.
研究领域:
材料科学
·
电化学
·
储能
·
计算材料科学
✓ 已验证
DOI
高影响因子
Small
·
2021
·Vol. 17
·期 45
·2104557
·
IF 13.281
Guolong Wang,Yaling Wang,Boyuan Guan,Jiamei Liu,Yan Zhang,Xiaowei Shi,Cheng Tang,Guohong Li,Yingbo Li,Xiao Wang,Lei Li
MnO 2 -based material is one of the most promising cathode candidates of aqueous zinc-ion batteries (ZIBs), but its commercialization is hindered by the sluggish reaction kinetics and poor structural stability. Herein, a hierarchical framework consisting of core–shell structured carbon nanotubes@K-birnessite-MnO 2 enwrapped by graphene/carbon black bicomponent networks (CNT@KMO@GC) via a simple method for ZIBs is designed and developed. The hierarchical framework characterized with favorable K + preintercalation, δ-phase, and vertically aligned nanoflake arrays of KMO and 3D electrically conductive network shows the enhanced electronic/ionic conductivity and improved wettability with electrolyte, resulting in the fast charge/mass transport and stable structural stability of CNT@KMO@GC. When used as cathode in ZIBs, CNT@KMO@GC exhibits exciting electrochemical performance with remarkable capacity (405.5 mAh g −1 at 0.30 A g −1 ), high rate performance (166.6 mAh g −1 up to 10.0 A g −1 ), and impressive cycling stability (almost no capacity decay after 2000 cycles and 77.3% retention after 10 000 cycles at 10.0 A g −1 ). The energy storage mechanism of CNT@KMO@GC is clarified as H + /Zn 2+ coinsertion/extraction via electrochemical analysis and ex situ characterization. This study offers an innovative paradigm for the advance of ZIBs.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
PubMed
高影响因子
Advanced Energy Materials
·
2018
·Vol. 9
·期 1
·1802739
·
IF 21.875
Ang Gao,Min Li,Nannan Guo,Daping Qiu,Yan Li,Senhao Wang,Xia Lu,Feng Wang,Ru Yang
Novel and low-cost rechargeable batteries are of considerable interest for application in large-scale energy storage systems. In this context, K-Birnessite is synthesized using a facile solid-state reaction as a promising cathode for potassium-ion batteries. During synthesis, an ion exchange protocol is applied to increase K content in the K-Birnessite electrode, which results in a reversible capacity as high as 125 mAh g −1 at 0.2 C. Upon K + exchange the reversible phase transitions are verified by in situ X-ray diffraction (XRD) characterization. The underlying mechanism is further revealed to be the concerted K + ion diffusion with quite low activation energies by first-principle simulations. These new findings provide new insights into electrode process kinetics, and lay a solid foundation for material design and optimization of potassium-ion batteries for large-scale energy storage.
研究领域:
材料科学
·
电化学
·
能量存储与转换
·
电池技术
✓ 已验证
DOI
高影响因子
Energy Storage Materials
·
2021
·
IF 17.789
Xian-Zhi Zhai,Jin Qu,Juan Wang,Wei Chang,Hong-Jun Liu,Yu-Hao Liu,Hongfu Yuan,Xiaofeng Li,Zhong-Zhen Yu
ABSTRACT Structural unsteadiness and limited electrochemical kinetics upon cycling seriously impede further applications of birnessite cathodes for rechargeable aqueous zinc‑ion batteries (ZIBs), even though they have high voltage platforms and distinctively layered structures for preferable (de)intercalation of zinc ions. Herein, yolk-shell structured K-birnessite (K 0.48 Mn 2 O 4 ·0.49H 2 O)@mesoporous carbon nanospheres (KMOH@C) with rich oxygen vacancies are synthesized for the first time with a two-step diffusion-driven strategy of hydrothermal synthesis followed by etching with KOH. The transport of reaction ions is regulated by surface charge and pore structure of the carbon shells, thus K-birnessite is preciously transferred into the hollow mesoporous carbon (HMC) nanospheres. Furthermore, the etching effect of KOH and the confinement effect of HMC nanospheres generate intercalated K + and abundant oxygen vacancies into KMOH, leading to an excellent electrochemical kinetics. Meanwhile, HMC nanospheres also endow rapid electron/ion transport and stabilize the crystal structure of K-birnessite. Therefore, KMOH@C exhibits superior electrochemical performances with high reversible capacities of 412.7 and 122.2 mA h g ‒1 at 0.5 and 10.0 A g ‒1 than reported cathodes, respectively. Moreover, an exceptional cyclability of 129.6 mA h g ‒1 even after 6000 cycles at 3.0 A g ‒1 is achieved, making the KMOH@C cathode highly competitive for eco-friendly aqueous ZIBs.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）