Light-assisted delithiation of lithium iron phosphate nanocrystals towards photo-rechargeable lithium ion batteries

Abstract

Recently, intensive efforts are dedicated to convert and store the solar energy in a single device. Herein, dye-synthesized solar cell technology is combined with lithium-ion materials to investigate light-assisted battery charging. In particular we report the direct photo-oxidation of lithium iron phosphate nanocrystals in the presence of a dye as a hybrid photo-cathode in a two-electrode system, with lithium metal as anode and lithium hexafluorophosphate in carbonate-based electrolyte; a configuration corresponding to lithium ion battery charging. Dye-sensitization generates electron–hole pairs with the holes aiding the delithiation of lithium iron phosphate at the cathode and electrons utilized in the formation of a solid electrolyte interface at the anode via oxygen reduction. Lithium iron phosphate acts effectively as a reversible redox agent for the regeneration of the dye. Our findings provide possibilities in advancing the design principles for photo-rechargeable lithium ion batteries.

Integrated Photo‐Responsive Batteries for Solar Energy Harnessing: Recent Advances, Challenges, and Opportunities

“…Recently, a two‐electrode photo‐rechargeable LIB was designed and constructed by using the Li metal as the anode and LiFePO 4 nanocrystals with N719 dye as the hybrid photocathode (Figure a) . In such a LIB, during photocharging process, the photoexcited holes generated by dye‐sensitization could aid the chemical oxidation of LiFePO 4 nanoplatelets to FePO 4 at the photocathode.…”

Lithium Photo‐intercalation of CdS‐Sensitized WO3 Anode for Energy Storage and Photoelectrochromic Applications

“…The photoinduced Li-ion intercalationo ft he CdS-sensitized WO 3 anode described herein can be advantageously combined (see band alignment diagrami nF igure S12) with our recent work involving photoinduced de-intercalationo fa nL iFePO 4 (LFP) cathode [36] to build ap rototype photochargeable device. In this device, the functiono ft he electrodes will change from cathoded uring discharge (in the dark) to photoanode during photocharging (n-type sensitized LFP) and from anode during discharge to photocathode during photocharging( p-type semiconductor-sensitized WO 3 ).…”

Integrated Photorechargeable Energy Storage System: Next‐Generation Power Source Driving the Future

“…Zaghib et al reported LFP nanocrystals mixed with dye molecules as a hybrid photocathode. [ 89 ] Under illumination, a voltage (vs Li/Li + ) rise of an LFP/dye electrode system was obvious, as shown in Figure 7c, suggesting photoexcited holes by dye molecules oxidized LiFePO 4 to FePO 4 . Meanwhile, the photogenerated electrons were confirmed to form solid electrolyte interface at the anode via oxygen reduction.…”

“…Reproduced with permission. [ 89 ] Copyright 2017, Nature Publishing Group. d) Bandgap excitation, photo‐oxidation, and Li + reduction when the device is exposed to incident light.…”