Tao Lu,Zhonghua Zhang,Bingbing Chen,Shanmu Dong,Chengdong Wang,Aobing Du,Longlong Wang,Jun Ma,Guanglei Cui
Magnesium batteries are recognized as a potential alternative to lithium ion batteries benefited from the advantages of low cost, high safety, and high energy density . But the development of magnesium batteries suffers from the sluggish motion of Mg 2+ in solid electrodes due to strong polarization. Compounds explored to accommodate magnesiation/demagnesiation, suffer from low capacity, sluggish kinetics and poor cycling performance. In this manuscript, copper current collector aided tellurium (Te) as the cathode material of magnesium battery is proposed. Due to superior electronic structure of Te atom, both reactants and products of cathode reaction exhibit metallic conductivity which accelerates the magnesiation/demagnesiation process This material delivers a specific capacity of 338 mAh/g at 100 mA/g, and keeps at 178.5 mAh/g after 400 cycles. Moreover, the electrode performs superior rate capability than the previously reported materials. A specific capacity of 265.4 mAh/g is achieved at 2 A/g without obvious polarization. Even at a very high current density of 3.75 A/g, a specific capacity of 118 mAh/g is still maintained. This study highlights the importance of electronic structure for multi-valent ion reaction related material, which also offers new strategy for cathode design of Mg batteries.
Rechargeable aluminum based batteries attract particular attention due to their high anode capacity, safety, and cost advantage. Recently, high discharge voltage, ultrahigh rate performance, and long cycle life of aluminum ion batteries have been reported. However, the capacity of these Al-based batteries is limited, and it is of great value to explore novel cathodes with high reversible capacity that can rival a rechargeable lithium ion battery. In this work, we present the redox process of a tellurium electrode in a Lewis acidic AlCl3/[EMIm]Cl room temperature ionic liquid and disclose, for the first time, that the tellurium not only can be reduced to Te2– but also can be oxidized to TeCl3+, and the whole process is reversible. Subsequently, we successfully construct a rechargeable Al–Te battery with an initial reversible capacity of ∼913 mAh/g, which is close to the theoretical capacity of tellurium of ∼1260.27 mAh/g and an obvious discharge voltage plateau at ∼1.5 V, already approaching that of a Li–Te battery (1.7 V). Significantly, this work brings a new way to reconsider the reaction mechanism and the theoretical capacities of chalcogen and its compounds as the cathode of the aluminum based batteries in room temperature chloroaluminate melts. For instance, the theoretical capacity of the sulfur is an unprecedented 5015.09 mAh/g when it undergoes a similar reversible redox process from S2– to SCl3+.
Feng Chen,Yuzhu Qian,Yaoyong Dong,Lijuan Chen,Ting Song,Yong Pei,Xianyou Wang,Xiongwei Wu,Bei Long
The rich valence states (−2 to +6) make elemental Te become a high-capacity electrode in aqueous batteries. The conversion process (Te to TeO 2 ) generates soluble Te 4+ species in aqueous electrolyte. The suppression of conversion process enables a long-term Te electrode at the cost of a partial storage capacity. Herein, a polyethylene glycol additive is introduced to regulate the electrolyte environment. The low H 2 O activity hinders Te 4+ species formation and therefore leads to the insertion-type Te electrode. The reshaped NH 4 + solvation structure facilitates the fast H 2 O removal and firm PEG adsorption on the electrode surface, also improving water-induced side reactions. This, coupled with the introduction of carbon host, contributes to a high-stability Te electrode. Theoretical and experiment studies reveal the reshaped NH 4 + solvation structure/hydrogen-bond network, the strong adsorption capability of B-doped carbon, and the inhibited Te dissolution. Additionally, a series of in/ex-situ characterizations prove the intercalation-type mechanism and the enhanced cycling stability. As a result, this elaborate electrode delivers a high reversible capacities of 376 mA h g −1 at 0.05 A g −1 and a long-term cycling stability with 73.8 % capacity retention at 5 A g −1 after 4500 cycles. This work provides a reference for the storage mechanism regulation in aqueous battery.
危险品化学品经营许可证（带存储）