Determination of lithium ions by stripping voltammetry using single-crystal LiFePO4

Determination of lithium ions is very important for extraction of lithium from salt lakes. Electrochemical sensor is an ideal choice, but it is not available so far. Here, a voltammetric sensor based on lithium iron phosphate (LiFePO 4 ) was developed. Single-crystal LiFePO 4 dominated by the (010) lattice plane was synthesized using hydrothermal method ; it had good selectivity for lithium ions. Lithium ions were preferentially intercalated into LiFePO 4 even if molar ratio of sodium ions , potassium ions , magnesium ions or calcium ions to lithium ions reached 10:1. The intercalation and deintercalation of interfering ions should be avoided because this reduced the selectivity of LiFePO 4 for lithium ions. Lithium ion concentration of synthetic Uyuni Salt Lake solution was determined using the standard addition method. The measurement result was only 0.34 % higher than the theoretical value. The sensor provides a highly selective lithium ion analysis method at an extremely low cost, which was very promising to be widely used.