Song Yexin,Chen Manjing,Zhong Ziyang,Liu Zhexuan,Liang Shuquan,Fang Guozhao
Developing practical technical index of aqueous zinc metal batteries (ZMBs) is crucial to support safe large-scale energy storage. However, the realistic performance demonstration of ampere hour (Ah)-scale aqueous ZMBs under high mass loading and large areal capacity, which is the key to the industrial application of aqueous ZMBs, remains a critical challenge. In this paper, we propose a bilateral in-situ functionalization strategy in response to the issues that face high mass loading and large areal capacity of aqueous ZMBs. A gradient interface of Zn negative electrode was formed by directional adsorption and in-situ decomposition of organic sodium salt electrolyte additive. It avoids the influences from the fluctuation of electrolyte state and positive electrode dissolution, realizing uniform large-capacity plating/stripping in Ah-scale pouch cell. The positive electrode interface was also in-situ modified by electrolyte additive, which not only facilitated ion intercalation but also suppressed positive electrode dissolution through adsorption at the interface, thereby achieving high-loading stability. As a result, the cyclic stability in coin cell maintained more than 4000 cycles at 2 A g −1 , underscoring the superior compared to its counterpart. More importantly, the Ah-scale pouch cell can last more than 680 cycles with an accumulated capacity of 319.6 Ah. This work offers a roadmap for designing practical Ah-scale ZMB pouch cells.
An Hanwen,Li Menglu,Liu Qingsong,Song Yajie,Liu Jiaxuan,Yu Zhihang,Liu Xingjiang,Deng Biao,Wang Jiajun
Polyethylene oxide (PEO) based electrolytes critically govern the security and energy density of solid-state batteries, but typically suffer from poor oxidation resistance at high voltages, which limits the energy density of batteries. Here, we report a Lewis-acid coordinated strategy to significantly improve the cyclic stability of 4.8 V-class PEO-based battery. The introduced Mg 2+ and Al 3+ with strong electron-withdrawing capability weaken the electron density of ether oxygen (EO) chains via chelation in the coordination structure, resulting in a locally limited interaction between the EO chains and the surface of cathodes at high state of charge. The batteries using Lewis-acid coordinated electrolytes and Ni-rich cathodes achieve high voltage stability of 4.8 V over 300 cycles. Further, the realization of industrial-scale electrolyte membranes, and Ah-level pouch cells over 586 Wh kg ‒1 with good cyclic stability, suggests the potential of our strategy in practical applications of all-solid-state batteries.
Stable lithium metal negative electrodes are desirable to produce high-energy batteries. However, when practical testing conditions are applied, lithium metal is unstable during battery cycling. Here, we propose poly(2-hydroxyethyl acrylate-co-sodium benzenesulfonate) (PHS) as negative electrode protective layer. The PHS contains soft poly (2-hydroxyethyl acrylate) and poly(sodium p-styrene sulfonate), which improve electrode flexibility, connection with the Cu current collector and transport of Li ions. Transmission electron cryomicroscopy measurements reveal that PHS induces the formation of a solid electrolyte interphase with a fluorinated rigid and crystalline internal structure. Furthermore, theoretical calculations suggest that the -SO 3 - group of poly(sodium p-styrene sulfonate) promotes Li-ion motion towards interchain migration through cation-dipole interaction, thus, enabling uniform Li-ion diffusion. Electrochemical measurements of Li | |PHS-coated-Cu coin cells demonstrate an average Coulombic efficiency of 99.46% at 1 mA/cm 2 , 6 mAh/cm 2 and 25 °C. Moreover, when the PHS-coated Li metal negative electrode is paired with a high-areal-capacity LiNi 0.83 Co 0.11 Mn 0.06 O 2 -based positive electrode in multi-layer pouch cell configuration, the battery delivers an initial capacity of 6.86 Ah (corresponding to a specific energy of 489.7 Wh/kg) and, a 91.1% discharge capacity retention after 150 cycles at 2.5 mA/cm 2 , 25 °C and 172 kPa.