Co-substitution Strategy for Boosting Rate-Capability of Lithium-Superionic-Conductor (LISICON)-Type Anode Materials in γ-Li3VO4Li4GeO4Li3PO4 Quasi-Ternary-System
Co-substitution Strategy for Boosting Rate-Capability of Lithium-Superionic-Conductor (LISICON)-Type Anode Materials in γ-Li3VO4Li4GeO4Li3PO4 Quasi-Ternary-System
复制标题
提高γ-Li3VO4Li4GeO4Li3PO4准三元体系中锂超离子导体（LISICON）型负极材料倍率性能的共取代策略
DOI：
10.1149/1945-7111/acaf40
复制
发表时间：
2023
影响因子：
3.9
通讯作者：
Naoi Katsuhiko
中科院分区：
文献类型：
--
作者：
Matsumura Keisuke;Iwama Etsuro;Tomochika Yuka;Matsuura Taro;Naoi Wako;Naoi Katsuhiko
利用简单的固态煅烧技术，成功合成了具有锂超离子导体（LISICON）相关晶体结构的γ-Li 3+ x v1 - x - y Ge x P y o4 （LVGePO）负极材料，用于具有高能量和高功率密度的下一代储能应用。在Li - 3vo - Li - 4geo - Li - 3po4体系的准三元相图中，阐明了它们的化学组成、晶相形成和速率性能之间的相关性。g4 +和/或p5 +取代比可以控制晶相的形成和表面稳定性；5%或更多的g4 +取代导致了具有高Li+电导率的纯γ相结构，而p5 +的存在抑制了SEI的形成。在Li 3.05-3.1 V 0.7-0.8 Ge 0.05-0.1 P 0.1-0.25 O 4的典型化学成分范围内，通过对化学成分的精细调整，在10 A g-1条件下获得了最高的电荷（衰减）容量，约为理论容量的62%（约为40c率），具有γ相晶体结构。与Li 3+ x v1 - x Ge x o4和Li 3v1 - y py o4的二元固溶体相比，这种共取代的LVGePO阳极表现出优越的速率性能。其电化学性能的提高是由共取代阳离子的不同作用引起的，即p5 +抑制了电解质在LVGePO晶体表面的还原性分解，而g4 +稳定了高Li+导电性的γ相结构。
Using simple solid-state calcination, γ-Li 3+ x V 1–x–y Ge x P y O 4 (LVGePO) anode materials with lithium superionic conductor (LISICON)-related crystal structures have been successfully synthesized for next-generation energy storage applications with high-energy and high-power densities. The correlation among their chemical compositions, crystal-phase formations, and rate performances has been elucidated and mapped in the quasi-ternary phase diagram of the Li 3 VO 4–Li 4 GeO 4–Li 3 PO 4 system. The crystal phase formation and surface stability can be controlled by the Ge 4+-and/or P 5+-substitution ratio; 5 at% or more Ge 4+-substitution resulted in a pure γ-phase structure with high Li+ conductivity, while the presence of P 5+ suppressed the SEI formation. Fine-tuning of the chemical composition brings about the highest charge (delithiation) capacity retention of ca. 62% of the theoretical capacity at 10 A g–1 (ca. 40C-rate) obtained in the typical chemical composition range of Li 3.05–3.1 V 0.7–0.8 Ge 0.05–0.1 P 0.1–0.25 O 4 with the γ-phase crystal structure. Such co-substituted LVGePO anodes exhibited superior rate performances compared to any binary solid solutions of Li 3+ x V 1–x Ge x O 4 and Li 3 V 1–y P y O 4. The improvement in the electrochemical performances are induced by the distinct roles of co-substituted cations, viz., P 5+ suppresses the reductive decomposition of electrolytes on the LVGePO crystal surfaces, while Ge 4+ stabilizes the high Li+ conductive γ-phase structure.