Layered-spinel heterostructured lithium-rich Mn-based oxides with dual-phase synergy: Interfacial engineering boosts capacitive deionization-based lithium extraction from low-grade brines

Surface spinel reconstruction on Li-rich Mn oxide mitigates Jahn-Teller distortion and Mn dissolution, 87% after 80 cycles. • S-LMCN enables rapid Li extraction with 42.25 mg g−1 capacity in 40 min, which demonstrates exceptional kinetics. • The heterostructure reduces the activation energy barrier for Li + charge transfer by 23.98% and it significantly decreases the charge-transfer resistance and facilitating interfacial Li + transport. • The S-LMCN in HCDI enabled highly selective lithium extraction, with an energy consumption as low as 2.07 kWh per Manganese-based electrodes for electrochemical lithium extraction from salt-lake brines are plagued by structural instability induced by the Jahn–Teller effect and poor electronic conductivity. These challenges result in significant capacity degradation and high energy costs for extracting Li + selectively. To tackle these issues, this work investigates a lithium-rich manganese-based layered-spinel heterostructure combined with a low-energy hybrid capacitive deionization system. The heterostructure establishes effective pathways for Li + transport to improve selectivity even in low-quality brines, while also reducing manganese dissolution caused by the Jahn–Teller effect and ensuring long-term cycling stability. Specifically, with these dedicated Li + transport channels in place, the energy barrier for electrochemical lithium extraction, as reflected by the activation energy (Ea) for Li + charge transfer, is reduced by 27.34% (from 29.70 to 21.58 kJ mol −1 ). This reduction facilitates a rapid, high-capacity uptake of 42.25 mg g −1 within 40 min. Furthermore, in comparison to the layered parent material, manganese dissolution is suppressed from 35.72% to 11.74%, resulting in an absolute reduction of 23.98 percentage points, even after undergoing 80 cycles. Download: Download high-res image (405KB) Download: Download full-size image