Lai Guojun,Zhao Zequan,Zhang Hao,Hu Xueting,Lu Bingan,Liang Shuquan,Zhou Jiang
Engineering the formulation of an Mn-based positive electrode is a viable strategy for producing an efficient aqueous zinc-ion battery. However, Mn dissolution and the byproducts result in capacity fading, thus limiting its electrochemical performances. To solve the undesirable issues, the concept of in-situ forming the positive electrode/electrolyte interface on the commercial MnO 2 is designed, with the help of introducing the Dioctyl Phthalate into the ZS-based electrolyte (2 M ZnSO 4 + 0.2 M MnSO 4 ), designated as ZS-DOP electrolyte. An advanced three-dimensional chemical and imaging analysis on a model material reveals the dynamic formation of positive electrode/electrolyte interface. The formed organic interface effectively suppresses the corrosion of the electrolytes with its hydrophobicity, and adjusts the pH value according to Le Chatelier’s Principle to inhibit the production of by-products. Specifically, the pouch cell assembled with the ZS-DOP electrolyte attains a reversible capacity of ~2.5 Ah and powers the unmanned aerial vehicle. Furthermore, photovoltaic energy storage applications deliver a stable capacity of 0.5 Ah and realize the power supply for mobile phones and other electronic devices. Our results facilitate the development of in-situ surface protection on the positive electrode in aqueous zinc-ion battery, providing insights into its practical application.
Qian Liu,Li Zhang,Xuna Liu,Zhongquan Zhong,Wei Deng,Ping Yang
Lithium ion-sieve with selective adsorption capacity is an important research direction in the field of recovering lithium from brine. The lithium ion-sieve precursor Li 1.6 Mn 1.6 O 4 was efficiently prepared using a combination of the hydrothermal method and solid-phase calcination. Subsequently, a highly adsorbent with high adsorption capacity was obtained through a process involving pickling and Li leaching. The impact of different preparation routes and conditions on both the intermediate product LiMnO 2 and the ion-sieve precursor Li 1.6 Mn 1.6 O 4 were investigated. Under conditions of 25 °C, pH 9, and an initial Li + concentration of 100 mg/L, the initial adsorption capacity and Mn dissolution loss are relatively optimal. After 10 cycles, the adsorption capacity stabilizes at 25–30 mg/g, However, Mn dissolution loss is unavoidable, it stabilizes between 2.0 % and 2.5 %. The selective adsorption of Li + remains effective even in the presence of Ca 2+ , Mg 2+ , Na + , and K + interference. Li desorption and Mn dissolution loss were investigated using density functional theory, Fukui function, electron orbital theory, and density of states. The introduction of H + during the pickling process induced structural modifications in the ion-sieve precursor Li 1.6 Mn 1.6 O 4 , leading to a decrease in Mn-Mn bonds, Mn-O bonds, and Li-O distances. Initially, Li + at each site of Li 1.6 Mn 1.6 O 4 had an equal probability of being replaced by H + . Subsequent desorption occurred far away from the desorption point. The loss of Mn 3+ in Li 1.6 Mn 1.6 O 4 resulted in an increased electrophilic attack index at the H + substitution site, and the 3d orbital electrons of Mn 3+ migrate to the 4d and 2p orbitals to seek stability.
LiNi 0.5 Mn 1.5 O 4 (LNMO) is a high-profile cathode material for lithium-ion batteries with high voltage and high specific energy. However, its practical application is severely hindered by the dissolution of Mn, primarily induced by the Jahn-Teller effect, which leads to significant capacity degradation, especially under high current densities. In this research, LiNi 0.5-7/3x Cu x Al x Mn 1.5-7/3x Ti x V x O 4 (x = 0, 0.5 %, 1 %, 3 %) was synthesized via a sol–gel method employing a multivalent ion co-doping strategy, denoted as CATV. X-ray diffraction analyses that the increase in the (311)/(400) peak ratio of CATV-1 % indicates a higher concentration of Mn 3+ , which enhances the structural disorder of the material, thereby improving its electronic conductivity. By improving the ratio of the (110) plane, which is perpendicular to the lithium-ion diffusion pathway, the lithium-ion diffusion coefficient was enhanced by three orders of magnitude. Furthermore, the Mn dissolution issue originating from the (111) plane was mitigated which shows in XRF that the Mn content deposited on the negative lithium sheet was reduced by 50 %. Specifically, it delivered specific capacity of 136.2 mAh·g −1 at 0.1C and maintained 81.74 % of its capacity after 300 cycles at 1C. Under 20C charge–discharge condition, it reached 108 mAh·g −1 , doubling that of the undoped sample. These findings provide new possibilities for the commercial application of CATV materials.
危险品化学品经营许可证（带存储）